Chastening is best associated to a parent-child relationship (Deuteronomy 8:5; 2 Samuel 7:14; Proverbs 13:24; Proverbs 19:18; Hebrews 12:6-8). As such, God’s chastening, at least within the New Testament, is only intended for those He calls His sons (1 John 3:2). God chastens His children, not to administer justice, but to strengthen and correct them. The believer does not receive some type of punishment from the Lord resulting from the believer’s sins because these sins have been completely atoned through the shed blood of Christ. However, the saint’s continued practice of sin requires the chastening hand of the Lord in order to conform him into the image of Christ. While chastening is reserved exclusively for sons, a lost man receives only punishment or salvation.
Fasting, similar to other actions in life, has specific purposes and appointed times. The Bible offers various reasons why people might fast: an immediate need in prayer (2 Samuel 12:16), a need to loosen the bands of wickedness or undo heavy burdens (Isaiah 58:6), during times of elevated conflict or duty in service (Matthew 17:21; Acts 13:3), as a symbol of mourning (2 Samuel 1:12), and as an outward manifestation of true repentance (Jonah 3:5). This list is not exhaustive, but simply demonstrates that God’s people have many good reasons for fasting. Even if none of these circumstances surfaces in our lives, we should fast because we know that the Lord expects us to do so.
