Definition and Purpose
Fasting, in the biblical context, is the voluntary abstention from food, and sometimes drink, for a spiritual purpose. It is a practice intended to humble oneself before God, seek His guidance, express repentance, or prepare for spiritual endeavors. Fasting is often accompanied by prayer and is seen as a means to draw closer to God, demonstrating dependence on Him rather than on physical sustenance.

Old Testament Examples
Fasting is a well-documented practice in the Old Testament. One of the earliest references is found in the Book of Leviticus, where the Israelites are commanded to "afflict your souls" on the Day of Atonement (Leviticus 16:29-31), which is traditionally understood to include fasting. In the Book of Esther, Queen Esther calls for a fast among the Jews before she approaches the king, saying, "Do not eat or drink for three days, night or day" (Esther 4:16).

The prophet Daniel also practiced fasting as a means of seeking divine insight and favor. Daniel 9:3 states, "So I turned my attention to the Lord God to seek Him by prayer and petitions, with fasting, sackcloth, and ashes" . This demonstrates fasting as an integral part of earnest prayer and supplication.

New Testament Teachings
In the New Testament, Jesus provides instruction on fasting in the Sermon on the Mount. He emphasizes the importance of sincerity and humility, warning against fasting for the sake of public recognition: "When you fast, do not be somber like the hypocrites, for they disfigure their faces to show men they are fasting. Truly I tell you, they already have their reward" (Matthew 6:16). Instead, Jesus instructs, "But when you fast, anoint your head and wash your face, so that your fasting will not be obvious to men, but only to your Father, who is unseen" (Matthew 6:17-18).

The early church also practiced fasting, often in conjunction with prayer, as seen in Acts 13:2-3, where the church in Antioch fasted and prayed before sending out Barnabas and Saul on their missionary journey. This indicates that fasting was a means of seeking divine direction and empowerment for ministry.

Spiritual Significance
Fasting is not merely a physical act but a spiritual discipline that reflects a heart posture of humility and dependence on God. Isaiah 58:6-7 highlights the kind of fasting that pleases God: "Is not this the fast that I have chosen: to loose the chains of wickedness, to untie the cords of the yoke, to set the oppressed free, and to break every yoke? Is it not to share your bread with the hungry, to bring the poor and homeless into your home, to clothe the naked when you see him, and not to turn away from your own flesh and blood?" . This passage underscores that true fasting is accompanied by acts of justice, mercy, and compassion.

Practical Considerations
While fasting is a powerful spiritual practice, it should be approached with wisdom and discernment. Individuals should consider their health and physical condition, seeking medical advice if necessary, especially for extended fasts. The focus should remain on the spiritual objectives of fasting, such as seeking God's will, interceding for others, or deepening one's relationship with the Lord.

In summary, proper fasting is a biblically endorsed practice that, when done with the right heart and motives, can lead to profound spiritual growth and alignment with God's purposes.