HH, Sir Godfrey Gregg D.Div
Throughout much of the Old Testament, there was only one fast day, the Day of Atonement (Leviticus 16:29). Later, other fasts were called for either because of a state of emergency or on the anniversary of a national tragedy (Zecharias 7:3-4). Fasting was an attempt to end a terrible circumstance.
In the new covenant, we fast in a different way, as after the wedding feast (Mark 2:20). We fast not only to end tragedy but to begin ministry. Jesus fasted for 40 days to begin His public ministry (Matthew 4:2). The church of Antioch fasted to begin the first missionary journey (Acts 13:2). We fast not so much because of destruction and tragedy but because of construction and fulfilment.