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Last Sunday evening our sermon on Isaiah 58 at Emmanuel raised the subject of fasting. While I hasten to point out that this was not the main area of application of the sermon (!), it's a reasonable question to ask how the Old Testament practice of fasting relates to Christians today.

Perhaps unsurprisingly I've always felt more drawn to the practice of feasting than fasting, but I've had to admit there are reasons to give the latter a closer look, which is the point of this post.


For those short on time or patience, here is my up-front summary of what this post argues:

Should Christians fast? No

May Christians fast? Yes

By which I mean fasting is not a New Testament command in the same way that other spiritual practices (prayer, sitting under the preaching of God's Word, baptism, the Lord's Supper) are. We can't simply read the Old Testament practice of fasting as a model for today without an appreciation of the transformation of our discipleship in Christ. No one needs feel their spiritual life is missing something major without fasting.
But on the other hand fasting is a perfectly valid option for Christians (and churches) to consider using as part of the way they practice relationship with God. We are embodied creatures by design: our minds are deeply affected by our bodily state, and this is the way it's supposed to be (not a result of the fall). As long as we are clear that any spiritual good from the practice will result from the Spirit's work in our hearts, it can be a helpful way of focusing ourselves on our relationship with God, especially in prayer, for a particular period.

For justification and further unpacking of those claims, read on.

What is fasting?

First, a definition:

Fasting is going without some created good (often food) that you would normally enjoy, for the sake of some spiritual good.

Fasting in the Bible

In the Old Testament, fasting appears as a general command only with regards to the Day of Atonement (Lev 16:19). When we see recorded incidents of the people fasting, it is associated either with corporate mourning (2 Samuel 1:12), confession of sin (2 Kings 21:27, Jonah 3:5), or as going along with a specific period of prayer about an upcoming decision (2 Chron 20:3) or particular concern (Ezra 8:21).
This makes sense in light of the definition above: fasting could express and heighten the feeling of loss (mourning) or grief at sin (confession), or the sense of dependence upon God (prayer). At the very least, a constant sense of hunger serves as a reminder that one is in a special period of time for a purpose.
In the New Testament, the church in Acts is only recorded as having fasted as part of times of prayer about specific decisions (Acts 13:3, 14:23). There is no reference to fasting in the letters. Both features are significant, but even more so is the teaching of Jesus on the subject in the gospels.

Jesus, fasting and the flow of history

In the Sermon on the Mount (from Matthew 6:16), Jesus says:
16 “When you fast, do not look sombre as the hypocrites do, for they disfigure their faces to show others they are fasting. Truly I tell you, they have received their reward in full. 17 But when you fast, put oil on your head and wash your face, 18 so that it will not be obvious to others that you are fasting, but only to your Father, who is unseen; and your Father, who sees what is done in secret, will reward you.
Some have read in the words "When you fast" a strong implication that Christians will and should continue to fast. But we need to remember that the Sermon on the Mount is Jesus' teaching directed to his disciples in the cultural and historical situation in which they found themselves. Matthew 5:23 is directed, for example, at the disciple "offering your gift at the altar" - an impossibility for us today. That does not mean the verse no longer applies to us, only that some work needs to be done to translate it to our situation.
An assumption that Jesus' first century disciples would be fasting, and that that was a good thing (or at least not a bad thing), is not the same as a mandate to do the same for all Christians throughout history. The focus is entirely on the right manner in which to fast, rather than how important the practice is.
In fact, Jesus' teaching on fasting elsewhere implies at least one period of time at which fasting was not appropriate. In Matthew 9:14, Jesus responds to a question put to him about his disciples and the practice of fasting:
14 Then John’s disciples came and asked him, “How is it that we and the Pharisees fast often, but your disciples do not fast?”
15 Jesus answered, “How can the guests of the bridegroom mourn while he is with them? The time will come when the bridegroom will be taken from them; then they will fast."
In this dialogue, Jesus picks up on the association of fasting with mourning, and says that it would be inappropriate for his disciples to fast while he is with them, a time of joy. There is a time when fasting will again become appropriate, "when the bridegroom will be taken from them" - the time of his impending arrest, trial and death. The joy of the arrival of the Messiah is taken away by his rejection by the people of Israel. At this time, his disciples will be thrown back into mourning.
But that period of mourning is short, for, gloriously, the tomb is emptied on the third day, and the bridegroom is restored to them by his resurrection. Jesus' subsequent ascension to heaven is not his "being taken away", for not only is he clear that "I am with you always, to the end of the age" (Matt 28:20), but the New Testament does not portray the ascension as a deprivation. It is for our good that Christ ascends, to reign from his heavenly throne and dispense to his people the gift of the Spirit.
So I don't think we have very strong reason from Jesus' words to conclude confidently that he expected and wanted his church to fast in the post-resurrection era. What we can gather from his teaching is that fasting may be more, or less, or differently appropriate at different points of salvation history, and that manner in which the practice is engaged in is all-important (a point on which Isaiah 58 agrees!).

Free to fast

Despite that, fasting is not something we need to entirely consign to the past.
As far as our position in history is concerned, our present experience of the Christian life is not marked by Jesus' absence but nor is it the fullness of what is to come in terms of being with him. Christ's bodily return to be with his people, the marriage supper of the Lamb, remains future. In that day, we may assume that fasting will be entirely swallowed up by feasting! But for the present time our Christian lives are marked by both the deep joy of Christ being with us by the Spirit, and a longing to see him face-to-face. Fasting isn't inappropriate for such a situation, as the practice of it by the church in Acts seems to bear out.
Nor should the move from Old Testament to New make us inherently suspicious of outward or external religious acts in themselves. We haven't gone from 'external' to 'internal' ways of relating to God, as if in the Old Testament what mattered were external ceremonies, but now the issue has become one of the heart. The worship of the old covenant was far more externally elaborate, yes, but the heart was always essential (see Deut 6:4-5, for example, or the many critiques of the prophets). And no new covenant, heart-renewed believer can practice relating to God without 'external' acts like prayer, meeting with God's people, or singing.
What matters, then as now, is that the act flows out of the heart. The act done without, or in opposition to, the heart is the problem of hypocrisy that Isaiah 58 lays bare. If a husband buys his wife flowers, does that prove he loves her? Indeed not; he may buy her flowers to keep her happy, or to compensate for a lack of attention, or out of mere habit. Yet the husband who never buys his wife flowers (or the equivalent: substitute your preferred act of love!) can't claim meaningfully to love her. An internal-only relationship isn't really a possibility. Heart and hands, intent and action, need to be together. The work of the Holy Spirit is key to this. It is his work to change the hearts of God's people, so that they can offer to God the right service (the external acts) that flow out of right hearts. Those externals can't achieve this root change, though they can subsequently be a means the Spirit uses to shape us.
If we start thinking about those 'externals' without this grid, we may either gain a false confidence that the acts by themselves will achieve heart change (forgetting the Spirit's role), or start to think that they are all an unnecessary afterthought (forgetting that we are embodied creatures whose actual lives matter).
Fasting needs to be read through this lens. It's a bodily act undertaken in order to focus the heart and the mind for a particular period of more concentrated practice of relating to God. In this way, it's not really any different from the practice of kneeling to pray, a bodily posture intended to focus the mind. We should treat it similarly: if it is helpful, we can make use of it, along as there aren't other considerations against it. Can kneeling help us to remember that we come before God humbly? Surely it can. But we would do well to consider, for example, if doing so in public setting would have the result of actually distracting others from their prayers. Can fasting help us concentrate our hearts on God for a particular period? Presumably the early church thought so. But at this point we would also do well to remember the target of Jesus' teaching on fasting in the Sermon on the Mount: the ease with which fasting became only an external work, done for the sake of the praise of men. Isaiah 58 lays bare this tendency in the history of Israel; Martin Luther notably said in a sermon, "I have never yet seen a right fast"! If your fasting makes it on to Instagram, it's safe to say something has gone wrong. 
It's also important to register that fasting is not part of the commanded practice of New Testament worship (at least, according to how I've read it here). So while a Christian life that is missing any of: prayer, singing, meeting with God's people, attending to Scripture or taking the Lord's Supper would be necessarily missing something vital, the same is not true of fasting. And having said that the move from Old Testament worship to New is not from external to internal, the radical simplification of the externals that are commanded is not arbitrary. The Christian today lives in the era of the Spirit, and as such we have a greater freedom, responsibility and equipping than the Old Testament believer to work out the external shape of our relationship with God.

Christian freedom

The upshot of all of that is to place fasting firmly within the area of Christian freedom. Just as the early church did, Christians today are free to make use of the practice of fasting as a means of concentrating ourselves on our relationship with God for a time, if and when that seems wise. We can do that individually, or corporately. There are reasons to think we shouldn't ignore the possibility of it being a useful thing: the God-given integrity of our hearts, minds and bodies for one. Perhaps we need to hear that message if we are tempted to dismiss the practice simply because it is outside our experience. But there's also reason to stay mindful of the potential pitfalls.
So happy fasting, or not!

About the author

Tom Underhill

Tom Underhill

Tom works part-time as Operations Manager at the South West Gospel Partnership, and part-time as a contract Web Developer. He is also doing postgraduate theology studies.

He is married to Katy and father of Jonny, Sophia, Benjamin and Noah. Previously he was an Associate at St Helens Bishopsgate.

Seeking to let God's Word speak and shape

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