What Is Fasting? Unger’s Bible Dictionary explains that the word fast in the Bible is from the Hebrew word sum, meaning "to cover" the mouth, or from the Greek word nesteuo, meaning "to abstain." For spiritual purposes, it means to go without eating and drinking (Esther 4:16).

The Day of Atonement—also called "the Fast" (Acts 27:9)—is the only fast day commanded by God (Leviticus 23:27), though other national fast days are mentioned in the Bible. Also, personal fasts are clearly expected of Christ’s disciples (Matthew 9:14-15).

We encourage those with health problems to consult a qualified medical practitioner before fasting.

Why Do You Fast?

The Bible gives examples of God’s people occasionally combining fasting with their prayers so as to stir up their zeal and renew their dedication and commitment to Him. King David wrote that he "humbled [him]self with fasting" (Psalm 35:13). Fasting is a means of getting our minds back on the reality that we are not self-sufficient. Fasting helps us realize just how fragile we are and how much we depend on things beyond ourselves.

The Bible records that great men of faith such as Moses, Elijah, Daniel, Paul and Jesus Himself fasted that they might draw closer to God (Exodus 34:28; 1 Kings 19:8; Daniel 9:3; 10:2-3; 2 Corinthians 11:27; Matthew 4:2). Jesus knew that His true disciples, once He was no longer there in the flesh with them, at times would need to fast to regain and renew their zeal to serve Him (Mark 2:18-20).

James tells us, "Draw near to God and He will draw near to you" (James 4:8). Constant prayer and occasional fasting help us to do this.

We are not to fast to have people feel sorry for us or to think we’re pious (Matthew 6:16-18). Isaiah 58 gives both bad and good examples of fasting, contrasting wrong attitudes and actions (verses 3-5) with the right approach of outgoing love (verses 6-10). Daniel and Nehemiah set the example of having a repentant frame of mind (Daniel 9:3-4; Nehemiah 9:1-2).

Fasting also helps us learn the lessons of the Day of Atonement: forgiveness, reconciliation to God and the need to resist Satan and pray for the time of his removal (Revelation 20:1-3), which was portrayed in type by the Azazel goat on Atonement (Leviticus 16:20-22).

—Sources: God’s Holy Day Plan and Transforming Your Life: The Process of Conversion.