We are addressing here strictly the Biblically described spiritual fasting — not fasting for health reasons. The fast during the Day of Atonement — one of God’s annual Holy Days — is the only commanded fast in the Bible (Leviticus 23:27, 29, 32). The fast on the Day of Atonement, referred to by the commandment to “afflict your souls,” has been rightly understood as abstaining from food and drink for 24 hours. (For more information, please read our free booklet, “God’s Commanded Holy Days.”). However, we find that God’s people fasted, or were asked to fast, on other occasions as well (compare, for example, Joel 2:12; Nehemiah 1:4; 2 Chronicles 20:3; Matthew 17:21; Daniel 9:3; Acts 13:2-3; Acts 14:23).
David, a man after God’s own heart, wrote in Psalm 35:13: “I humbled [or: afflicted] my soul with fasting.” Here, David fasted in the same way, as it was required on the Day of Atonement — by afflicting his soul. This would mean that he abstained from food and drink during his fast.
In fact, all Biblical passages, defining or describing the manner of fasting, make clear that it is being done by abstaining from food and drink. We read in Esther 4:16, that the queen told her uncle Mordecai: “Go, gather all the Jews who are present in Sushan, and fast for me; neither eat nor drink for three days, night or day. My maids and I will fast likewise.”
We also find that Ezra, who was accustomed to fast in times of need (compare Ezra 8:21-23), fasted in this way: “[He] ate no bread and drank no water, for he mourned because of the guilt of those from the captivity” (Ezra 10:6).
In addition, when Moses fasted for forty days and forty nights, “he neither ate bread nor drank water” (Exodus 34:28). There is NO Scripture that would tell us that people who engaged in spiritual fasting drank water or other fluids.
We also read that Elijah, after he ate and drank, what the angel had provided him, “went in the strength of that food forty days and forty nights as far as Horeb, the mountain of God,” (1 Kings 19:8) indicating that he did not eat or drink during these forty days and nights.
We note, too, that the Ninevites did not eat or drink during their fast (Jonah 3:7); and neither did the Jews who tried to kill Paul (Acts 23:12) — they, of course, fasted for a wrong reason. Still, this shows how the Jews understood the manner of fasting; in fact, Paul fasted by abstaining from food and drink for three days (Acts 9:9).
Some have suggested that Jesus Christ drank water, when He fasted for 40 days and 40 nights in the desert (compare Matthew 4:1-2). However, the Bible does not say that He drank water, and to conclude that He did, means to read something into the Bible which is simply not there.
We might want to add, however, that we do not recommend that anyone should fast today for 40 days and 40 nights or anywhere near that long. As we have reached the end of this degenerate age, to do so today would border on suicide. In addition, the principles discussed in this Q&A only apply in normal cases and circumstances, and not for people who are diabetic or suffer from other serious ailments. The Church of God has recommended a long time ago that a person with a medical condition should check with a medical doctor for advice in order to determine whether it is advisable and safe to fast at all, as described herein. In addition, children should not be required to fast. Children old enough to understand what their parents are doing may want to fast. It might be advisable for some children to start with a half-day fast.
In conclusion, a spiritual fast should be conducted by abstaining from food and drink.