Definition and Purpose:
Fasting, in the biblical context, refers to the voluntary abstention from food, and sometimes drink, for a specified period. It is often undertaken for spiritual purposes, such as seeking God's guidance, expressing repentance, or intensifying prayer. Fasting is a practice observed in both the Old and New Testaments and is associated with humility, devotion, and a deepening of one's relationship with God.

Old Testament Instances:
Fasting is frequently mentioned in the Old Testament as a means of humbling oneself before God. One of the earliest references is found in the context of the Day of Atonement, where the Israelites were commanded to "afflict their souls" (Leviticus 16:29-31), which is traditionally understood to include fasting. In 2 Samuel 12:16, David fasted and prayed for the life of his child. The book of Esther records a communal fast called by Queen Esther before she approached the king (Esther 4:16). The prophet Joel called for a sacred fast as a response to a national crisis, urging the people to "return to Me with all your heart, with fasting, weeping, and mourning" (Joel 2:12).

New Testament Teachings and Examples:
In the New Testament, fasting continues to be a significant spiritual discipline. Jesus Himself fasted for forty days and nights in the wilderness before beginning His public ministry (Matthew 4:2). He taught about fasting in the Sermon on the Mount, instructing His followers to fast discreetly and not for show: "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). Jesus also indicated that certain spiritual breakthroughs require both prayer and fasting (Mark 9:29).

The early church practiced fasting as part of their worship and decision-making processes. In Acts 13:2-3, the church in Antioch fasted and prayed before sending out Barnabas and Saul on their missionary journey. Similarly, in Acts 14:23, Paul and Barnabas appointed elders in the churches with prayer and fasting.

Theological Significance:
Fasting is seen as a way to humble oneself before God, to express repentance, and to seek divine intervention. It is an act of worship and devotion, reflecting a heart that is earnest in seeking God's will. Fasting is not merely a physical act but is deeply connected to prayer and spiritual reflection. It is a means of drawing closer to God, aligning one's heart with His purposes, and demonstrating dependence on Him.

Practical Considerations:
While fasting is a powerful spiritual discipline, it is important to approach it with the right motives. The Bible warns against fasting for the sake of appearance or self-righteousness. Isaiah 58:3-7 criticizes those who fast for selfish reasons, emphasizing that true fasting should lead to justice, compassion, and care for others. Fasting should be accompanied by prayer, meditation on Scripture, and a heart open to God's leading.

Conclusion:
Fasting remains a relevant and meaningful practice for believers today, offering a way to deepen one's spiritual life and seek God's presence in a focused manner.