Joel 2:12-15

Therefore also now, saith the LORD, turn ye even to me with all your heart, and with fasting, and with weeping, and with mourning: and rend your heart, and not your garments, and turn unto the LORD your God: for he is gracious and merciful, slow to anger, and of great kindness, and repenteth him of the evil. Who knoweth if he will return and repent, and leave a blessing behind him; even a meat offering and a drink offering unto the LORD your God? Blow the trumpet in Zion, sanctify a fast, call a solemn assembly