Truth #1 We can fast from good things other than food.
Fasting for spiritual purposes include:
strengthening prayer (Ezra 8:23; Joel 2:13; Acts 13:3)
seeking God's guidance (Judges 20:26; Acts 14:23)
expressing grief (1 Samuel 31:13; 2 Samuel 1:11-12)
seeking deliverance or protection (2 Chronicles 20:3-4; Ezra 8:21-23)
expressing repentance and returning to God (1 Samuel 7:6; Jonah 3:5-8)
humbling oneself before God (1 Kings 21:27-29; Psalm 35:13)
expressing concern for the work of God (Nehemiah 1:3-4; Daniel 9:3)
ministering to the needs of others (Isaiah 58:3-7)
overcoming temptation and dedicating yourself to the Lord (Matthew 4:1-11)
expressing love and worship to God (Luke 2:37)
"Fasting can be an expression of finding your greatest pleasure and enjoyment in life from God." - Donald Whitney , Spiritual Disciplines for the Christian Life
Truth #2 Jesus assumes believers will fast.
While the New Testament includes no mandate for Christians to fast, Jesus assumes that we will fast. (Matthew 6:16-18; Matthew 9:14-15; Acts 9:9; Acts 13:2; Acts 14:23)
Truth #3 Fasting puts an edge on believer's feelings.
Fasting helps focus our feelings and expressions toward God in prayer.
Fasting is saying with our whole bodies what prayer says with the heart: "I long to be satisfied with God alone!"