What is Fasting? Why is fasting? Can You Ruin Your Witness?

In the previous section of Jesus’ Sermon on the Mount (Matthew 5), we saw that Jesus addressed six popular teachings that were contrary to the actual message of the Old Testament after committing verbally to remaining faithful to the Old Testament Scriptures. The major way in which the Old Testament was misused, according to Jesus’ sermon, was in support of religious legalism. We even saw how the popular teaching of the day exceeded what was written. Jesus brought the people back to what the Scriptures stated in context. In the present section of His sermon to His disciples and in view of the large group of people (6:1-7:6), we see Jesus address not only the legalistic teaching but also the legalistic tendencies of the religious community. After teaching from the Old Testament that faith was a gift and a condition of the heart and after exposing how the Law was being mistaught, Jesus begins to expose the absurdity of majority human worldview.

As we continue through this section of Jesus’ sermon, we will see the way in which Jesus evaluates our religion and our participation in church (or the equivalent thereof).  Right practice (orthopraxis) follows right teaching (orthodoxy). Spiritually healthy people or groups don’t merely have one or the other but strive for both. In the context of this sermon, Jesus didn’t compare Pharisees, Sadducees, Zealots, Essenes, the Imperial Cult, and Eastern Religion- saying one was right and the others were wrong. Jesus got at real things and at the human heart. Let’s take a moment and not defend our own beliefs, churches, associations, denominations, or religions. Let us evaluate what is taught and what is practiced in our lives and in our churches the same way that Jesus does in this section of His sermon.

Matthew 6:16-24

“Whenever you fast, do not put on a gloomy face as the hypocrites do, for they neglect their appearance so that they will be noticed by men when they are fasting. Truly I say to you, they have their reward in full.

But you, when you fast, anoint your head and wash your face so that your fasting will not be noticed by men, but by your Father who is in secret; and your Father who sees what is done in secret will reward you.

Do not store up for yourselves treasures on earth, where moth and rust destroy, and where thieves break in and steal. But store up for yourselves treasures in heaven, where neither moth nor rust destroys, and where thieves do not break in or steal; for where your treasure is, there your heart will be also. The eye is the lamp of the body; so then if your eye is clear, your whole body will be full of light. But if your eye is bad, your whole body will be full of darkness. If then the light that is in you is darkness, how great is the darkness! No one can serve two masters; for either he will hate the one and love the other, or he will be devoted to one and despise the other. You cannot serve God and wealth.”

On fasting (v. 16-18)

We remember, as we begin this passage, that Jesus is dealing with legalistic religion and explaining that this legalistic religious practice is coming out of a misunderstanding or outright neglect of the Scriptures (either by tainting or hiding them). It makes sense that, after describing the popular legalistic teaching and practice of the day, Jesus would begin His explanation of a proper view of fasting by addressing legalistic religious practice- that of the hypocrites.

First, Jesus instructs His disciples not to be like the hypocrites in as they fast. The mark of a hypocrite’s fasting is that the motivation behind the act is that he or she may be seen by people. As we discovered last week and the week before, legalism necessarily leads to this sort of motivation. In the same way that Jesus teaches in verses 2 and 5, Jesus also teaches that those who fast like the hypocrites do have received their reward in full- having no reward with their Father who is in heaven.

Over the last two weeks when we looked at Matthew 7:21-23, we saw that the reward for God’s people is that they will enter the kingdom of heaven. That is eternal life, satisfaction, and rest. People obtain this reward by doing the will of the Father, which is explicitly not working, doing good or religious things, even in Christ’s name. It is explicitly being known by Christ. Legalism, then, actually makes people practitioners of lawlessness according to the Old Testament and to Christ. Throughout Jesus’ sermon, it is consistently and explicitly the case that practitioners of legalistic religion will have no reward with the Father and will have to depart from Jesus when that day comes. In the passage for today, we see that this is the second time Jesus has repeated this truth. Both times Jesus has said this, it has been with regard to some sort of legalistic religious practice.

While this is true, it is also assumed that those who follow Jesus Christ will fast. Jesus did not instruct His disciples to fast, but said, “Whenever you fast…” Like prayer, we see that fasting is fruit that is produced in the lives of Christ’s true disciples as a result of Christ’s work, which is the root. Just as we saw in verses 3 and 4, for those who are truly in Christ, there is only one motivator for good works, that their Father will see. When Jesus says, “…your Father…” (“your” is again singular here) the indication is that a personal relationship with the Father precedes the practicing of proper fasting (c.f. Philippians 3:9).

Genuine, real fasting, then, comes as a result of one having a personal relationship with God the Father in Christ (v. 3-4, in the singular), necessarily belong and are engaged in the body of Christ (v. 6 in the plural), and are drawn more deeply into a relationship with God the Father in Christ (v. 18 in the singular). Fasting, like prayer and like giving to those in need, is primarily personal and secret. There was no regular fasting until we see it with the Pharisees and John’s disciples as part of their outward religiosity (9:14). Fasting was practiced only on very special occasions, to seek the Lord’s will (Exodus 34:28, Deuteronomy 9:9, Ezra 8:21), during mourning or deep repentance (Judges 20:26, 1 Samuel 31:13, 2 Samuel 1:12, Nehemiah 1:4, Zechariah 7:3-5, 8:19). Isaiah even rebukes Israel for fasting in order to accomplish some result or to move God to action (Isaiah 58:3-6). Instead, the people were to fast to humble themselves before God and others. In Jesus’ case during the 40-day temptation, He fasted in order to accomplish all righteousness. First, it was preparation in the likeness of Moses on Mount Sinai (Exodus 34:28). Moses fasted for 40 days when giving God’s Law as a sign of the covenant. Jesus fasted for 40 days as He came to fulfill God’s covenant, signified by the Law. Second, it was an undoing of Israel’s 40-year failure in the wilderness- during which they complained that they did not have any food. Jesus’ fasting fits with both seeking God’s will and deep repentance as He accomplishes all righteousness not only for the chosen ones of Israel but also His chosen people who live among the nations.

Fasting, then, comes as a result of our recognition of our own depravity. It is not necessarily a regular practice, but one of deep repentance and mourning. Without a personal relationship with the Father in Christ, without being a committed member of a true body of believers, and without experiencing a true deepening of our personal relationships with God, we do not really experience this reward that Jesus teaches about. The reason we fast, voluntarily depriving ourselves of necessary sustenance, is because it reminds us personally of just how deprived we are without this relationship with God the Father in Christ (the Son). Fasting draws the people of God into deeper worship. We remember that it is fruit, not root.

Seeking rewards (v. 19-21)

At this point, Jesus has repeated Himself, mentioning rewards three times. In verse 19, Jesus follows this by instructing His disciples not to “build up treasure on earth, where moth and rust destroy, and where thieves break in and steal…”

Jesus is instructing His disciples not to practice their righteousness, whether by giving, praying, or fasting, in any way so as to gain some type of reward on this earth. Jesus has already said that those who do so receive their reward in full and will not enter the kingdom of Heaven (comp. 7:21). When Jesus gives this instruction, He is referring to more than merely money, though the connotation includes material wealth. Our problem is that when we present this verse, we often do so out of context and present it as if Jesus is merely referring to material wealth. Jesus instruction is deeper. His disciples are not concerned with building up for themselves a good reputation among people, they are not to be concerned with appearing to be righteous or pious, and they are not to be concerned with advancing their status or wealth in this world.

Instead, Jesus instructs His disciples to do exactly the opposite. They are to store up for themselves treasure in Heaven. The way that this is accomplished is in the disciple’s (and disciples’) motivation to simply please the Father as a result of the real relationship he or she (or they) have with the Father in Christ.

We have heard it said, “Don’t go to the bar, club, or liquor store because you might ruin your witness,” but a proper application of Jesus’ teaching is, “Don’t be so concerned about your personal reputation or religion that it causes you to fail at being Christ’s witness.”

Do we see how popular religion often takes Christ’s words and twists them to make application that is entirely contrary to what Jesus actually teaches in His Bible. The only way we ruin our witness is by not going and building relationships with sinners and by not sharing the Gospel everywhere in all places with all wisdom. Our piousness is not what brings people into Salvation. Christ does through the proclamation of His Gospel. It is our lives as depraved wretches that stand as the proper testimony to our desperate need of Jesus Christ.

Where our treasure is, there our hearts are also. If our treasure is money, success, personal reputation, our religiosity, and our own righteousness, that is where our hearts are. If our treasure is the righteousness and glory of God, we reveal that this is where our hearts are. This is personal, the “your” in verse 21 is also singular.

A true dichotomy (v. 22-24)

Verses 22-23 represent idiomatic language in the first-century Jewish culture that really doesn’t translate well into English, especially in the 21st century. It is likely that a reference to good eyes as the lamp of the body refers to healthy, generous motivation while bad eyes is a reference to unhealthy, greedy motivation. This interpretation makes the most sense within the literary context of the passage. If someone is properly motivated as a result of having a personal relationship with God the Father in Christ, the whole body is full of light. The imagery of light has already been used twice by Matthew to refer to God’s revelation in Christ (4:16) and through the teaching of God’s explicit written word through Christ’s disciples (5:14). In context, then, to be full of light is to be full of God’s life-giving self-revelation.

Conversely, if our motivation is poor, we show that God’s life-giving self-revelation is not in us. Instead, we are driven by religiosity and self-righteousness. If what we perceive as light within us is actually darkness, if we are fooled into thinking we are righteous because of our outward religiosity or good works, the darkness within us is great according to Jesus.

A person cannot be filled with both light and darkness. Jesus clarifies absolutely, “No one can serve two masters…” We cannot serve both God and religiosity. We cannot serve both our reputations and the pleasure of God. We cannot serve both our piety and God’s glory. We cannot both build our own material kingdoms and be a citizen of Heaven’s kingdom. We cannot have a reward both on this earth and with God everlastingly. Wherever our treasure is, that is where it is wholly and we cannot have a little here and a little there. We will either hate one and love the other or be devoted to one and despise the other. We cannot serve both God and wealth. Serve is the Greek word “δουλευειν,” meaning “to serve as a slave.” Wealth is the Greek word “μαμωνα,” is a literary personification of wealth and of the material thrust of the human heart, also realized in legalistic, outward religiosity. Jesus isn’t referring to ill-gotten gain, here. He is simply referring to the natural person’s love for money, stuff, reputation, and self-righteousness. We cannot serve these things in any way and also serve God.

Lest we become legalistic in this teaching, we remind ourselves that Jesus has already and will continue to teach a root produces fruit anthropology. A relationship with the Father in Christ precedes our ability to truly be filled with light and really serve God with all sincerity. By grace, God brings us, through sanctification, to untether from the ways of this world.

Old Testament use

Jesus is still expositing and applying the Old Testament message we have observed over the last two weeks in Jeremiah 17:5-11. Jesus alluded to this passage in Matthew 6:1-4 and will continue to make specific applications through the end of this section of His sermon to His disciples.


    1. How does majority religion water down the act of fasting (especially during lent) or use it as a legalistic means of righteousness?
    2. How do people often twist the Great Commission, forming it into legalistic religion?

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