2 Chronicles 20:3

And Jehoshaphat feared
Exceedingly, as the Targum adds, not merely because of the number of his enemies, for he had forces enough to go forth against them, see ( 2 Chronicles 17:14-19 ) , but chiefly because the Lord had told him that wrath was upon him from him, ( 2 Chronicles 19:2 ) and he might fear that this was the time for the execution of it: and set himself to seek the Lord;
by prayer and supplication, with all seriousness, fervour, and constancy: and proclaimed a fast throughout all Judah;
a day of humiliation and mourning for sin before the Lord; when they were ordered to abstain from bodily food and labour, that they might be fit and more at leisure for spiritual exercises.