Fasting has ordinarily been practiced as giving up food for a fixed time, and has been a fixture of the Christian tradition since its beginnings. One of the earliest Christian documents, the Didache, has several instructions regarding fasting that touch multiple aspects of life, which indicates that fasting’s importance was suffused throughout early piety. Drawing on Jesus’ words recorded in Matthew 5:44 and Luke 6:28, the Didache exhorts Christians to bless those who curse us, pray for our enemies, and fast for our persecutors (1:7). It further instructs new converts to fast in preparation for baptism (7:6–7). Lastly, and perhaps most broadly, it again joined fasting to a believer’s prayer life, and advised that Christians should fast on the fourth day of the week and the sixth in preparation for the Lord’s Day instead of on days that “the hypocrites” (i.e. the Pharisees) fast (8:1–2). These points from the Didache tell us that early Christians incorporated fasting into major parts of life, and took the practice seriously. The questions that rise from this ancient practice, and the topics addressed in this article, are why they would so devotedly observe it, whether it continued on through the ages of the church, and what that should tell us about how we should think about fasting.
The main reason why the early church fasted was because it is taught in Scripture and was passed down to them from Judaism, Jesus’ teachings, and the apostolic practice. Scripture records that God’s people fasted in conjunction with major events or when they were fervently seeking God in desperate times. In Exodus 34, when God gave the second set of tablets detailing the law, Moses was with God and fasted from bread and water for forty days and nights. In 1 Samuel 7, when Israel turned back to God in light of an impending Philistine attack, the nation fasted and confessed their sin to God. In 2 Samuel 1, as David and his men grieved Saul’s death, they fasted in mourning. In Ezra 8:21–23, the Israelites who would return from exile to the Promised Land fasted to seek the Lord in intense prayer for protection on their journey. In Nehemiah 1, the news that Jerusalem’s fortifications were destroyed provoked Nehemiah to prolonged fasting and prayer as he sought repentance among his people and their restoration before God. In Nehemiah 9, the people included fasting as a sign of their mourning as they repented of their sins. Clearly, Scripture records how people fasted to seek God in an intense way, most often conjoined with prolonged prayer, and that fasting was, far from being a mark of empty outward practice, supposed to mark true mourning over loss, true repentance over sin, or true humility in seeking God (Ps. 69:9–12; Is. 58:1–14; Jer. 36:1–9; Jl. 1:13–16; Jl. 2:12–16).
The New Testament also enjoined the same kind of sincere fasting, not for appearances, but for seeking God. In Matthew 6:16–18, Jesus warned his followers to avoid fasting like hypocrites, who do so in order to be seen. In Mark 2:18–22, he explained that his disciples did not fast while he was with them because fasting is for a time of mourning when their bridegroom is not with them. Fasting is often joined with worship and prayer (Lk. 2:37; Acts 13:2–3; 14:23). The New Testament view on fasting, therefore, stands in continuity with the Old Testament by endorsing fasting as a way to repent of sin, mourn over loss, or intensely seek God in prayer and worship.
Interestingly, the Scripture never demands that Christians fast, which raises the obvious question about its continuation. The Scripture does speak positively of fasting, and Jesus’ language of “when you fast” assumes that his followers would be doing it. In a complementary way to how the Scripture commends fasting, church history exhorts Christians to fast. Justin Martyr (c.100–165), one of the first Christian apologists, picked up the instruction of the Didache for new converts to seek God in fasting before being baptized. Tertullian (c.160–225) also advocated for pre-baptismal fasting, but further wrote an entire treatise on fasting. In On Fasting, he argued that gluttony and the love of food are tied to the fleshly nature that came about after Adam’s Fall. He strongly set physical against the spiritual strength, arguing that intense fasting and specific dietary restrictions were for a person’s spiritual good.
A focus on fasting did not quell over the centuries and the emphasis developed on how fasting helped the spiritual life. In the medieval period, Thomas Aquinas (1225–74) argued that fasting is virtuous because it helps bridle the lusts of the flesh and to set the mind more on contemplating heavenly things. Martin Luther (1483–1546) continued to promote the two reasons for fasting that Thomas outlined. Luther wrote, “Of fasting I say this: it is right to fast frequently in order to subdue and control the body. For when the stomach is full, the body does not serve for preaching, for praying, for studying, or for doing anything else that is good. Under such circumstances God’s Word cannot remain. But one should not fast with a view to meriting something by it as by a good work.” John Calvin (1509–64) argued that pastors should exhort God’s people at specific times of need to pursue God in fasting, supplication, and other acts of deference and repentance. He outlined the purposes of fasting very much like Thomas and Luther, arguing that fasting is for subduing sin, for preparing for prayer and meditation, and for showing our humility and repentance before God. Fasting clearly remained an important feature of church life through the ages.
Interestingly, however, Calvin said that fasting had more use as a corporate exercise than for private individuals, which is a point often missed in modern discussions of fasting. Richard Foster, for example, emphasizes the role of all spiritual disciplines for the inward spiritual life. The benefits for the personal spiritual life are obviously not in absolute conflict with corporate fasting, but it is interesting that most of the Old Testament examples cited above described God’s people together seeking the Lord through fasting. That corporate aspect was never at odds with the purposes laid out through the patristic, medieval, and Reformation period either. Foster, in contrast to that tradition, says, “In most cases, fasting is a private matter between the individual and God. There are, however, occasional times of corporate or public fasts.” Most likely, Foster simply wanted to exclude hypocritical versions of visible fasting, but still, he described fasting’s benefits in terms of self-exploration whereby we might discover more emotional sin or bring ourselves to new levels of discipline. Moreover, Dallas Willard highlights fasting even more as a means of learning self-denial, which seems to emphasize introspection or mystical self-improvement over the traditional emphasis on repentance and worship. These more individualistic approaches, even with Foster’s proper and biblical qualifications, seem not to square entirely with the Bible and the historic church’s emphasis on fighting sin and serving to aid prayer and worship.
The last matter to consider is how Reformed Christians should think about fasting today. Especially in this season that people know as Lent and with an apparent rise in Lent’s trendiness among Reformed and even secular people, it is worth thinking about fasting not just as a discipline of the Christian life, but also in terms of whether we should participate in something like Lent. Although some have argued that Christians must be committed to the scheduled Church fasts, that ceremonial calendar of fasting does not seem to match the biblical pattern of fasting when there is an urgent need to see God work or the patristic and Reformation pattern of fasting to repent of sin and prepare for worship. There is no doubt that Scripture and church history commend fasting to us, and, obviously in consideration of medical wisdom and personal circumstances, we should all undertake the practice of fasting at times. It seems better, however, to do that in conjunction with a specific need to repent or seek God as an individual or as a congregation than to do so as part of a liturgical fast.
There has been, especially accompanying Lent’s increased cultural popularity, a growing practice of fasting not just from food, but from various aspects of life. Some people give up chocolate or the internet—I’ve even known one person who gave up saying “yes” to people—as matters of fasting. This is an interesting trend, and it would be easy to adopt it wholesale or dismiss it as silly. Interestingly, even if he clearly thought of food as fasting’s first application, Calvin did not limit fasting to giving up meals. He thought that giving up food for certain limited periods was one marker of a tempered life that should characterize Christians. Paul taught that married couples can abstain from conjugal activities for a time to focus on prayer, which seems to be a type of fasting from something other than food (1 Cor. 7:5). In our age that is filled with countless distractions, perhaps it is worth thinking about what most pulls us away from focused repentance and worship. It is worth making sure that we are ready to set aside and deprive ourselves of the things that may leave us complacent in our sin, distract us from prayer, or leave us less than ideally prepared for worshipping our God.
Harrison Perkins (PhD, Queen’s University Belfast) is the assistant minister at London City Presbyterian Church (Free Church of Scotland), a lecturer in Christian doctrine at Cornhill Belfast, a visiting lecturer in systematic theology at Edinburgh Theological Seminary, and the author of Catholicity and the Covenant of Works: James Ussher and the Reformed Tradition (Oxford University Press, forthcoming).
 Find the text of the Didache in Michael W. Holmes (ed.), The Apostolic Fathers: Greek Texts and English Translations, 3rd ed. (Grand Rapids, MI: Baker Academic, 2007), 344–69.
 Although one of Jesus’ most famous teachings about fasting links it to prayer in seeking God to help cast out demons, the manuscript evidence omits at least the reference to fasting (Mk. 9:29) if not the entire verse (Mt. 17:21).
 Justin Martyr, First Apology, LXI in Alexander Roberts and James Donaldson (eds.), The Ante-Nicene Fathers, 10 vols. (New York, NY: Charles Scribner’s Sons, 1913), 1:183. (This collection will henceforth be abbreviated ANF).
 Tertullian, On Baptism, 20 in ANF 3:678–79; Tertullian, On Fasting in ANF 4:102–15
 Tertullian, On Fasting, 3 in ANF 4:104.
 Thomas Aquinas, Summa Theologiae, trans. by Fathers of the English Dominican Province, 5 vol. (Notre Dame, IN: Christian Classics, 1948), 2a2ae.147.1. He also claimed in this article that fasting satisfied for sin, but that is inconsistent with a Protestant appropriation of Thomas.
 Martin Luther, What Luther Says, compiled by Ewald M. Plass, 3 vols. (St. Louis, MO: Concordia Publishing House, 1959), 1:506.
 John Calvin, Institutes of the Christian Religion, trans. by Ford Lewis Battles, ed. by John T. McNeil (Louisville, KY: Westminster John Knox Press, 1960), 4.12.14, 17.
 Calvin, Institutes, 4.12.15.
 Richard J. Foster, Celebration of Discipline: The Path to Spiritual Growth, rev. ed. (London: Hodder and Stroughton, 1989), 1–11.
 Foster, Celebration of Discipline, 64.
 Foster, Celebration of Discipline, 69–71.
 Dallas Willard, The Spirit of the Disciplines: Understanding How God Changes Lives (New York, NY: HarperOne, 2009), 166–68.
 For an example of the argument that Christians should keep the Church’s scheduled fasts, see Thomas, Summa Theologiae, 2a2ae.147.3–5.
 Calvin, Institutes, 4.12.18.