Joel 2:15

15 Blow the ram’s horn in Jerusalem! Announce a time of fasting; call the people together for a solemn meeting.

Joel 2:15 In-Context

13 Don’t tear your clothing in your grief, but tear your hearts instead.” Return to the LORD your God, for he is merciful and compassionate, slow to get angry and filled with unfailing love. He is eager to relent and not punish.
14 Who knows? Perhaps he will give you a reprieve, sending you a blessing instead of this curse. Perhaps you will be able to offer grain and wine to the LORD your God as before.
15 Blow the ram’s horn in Jerusalem! Announce a time of fasting; call the people together for a solemn meeting.
16 Gather all the people— the elders, the children, and even the babies. Call the bridegroom from his quarters and the bride from her private room.
17 Let the priests, who minister in the LORD ’s presence, stand and weep between the entry room to the Temple and the altar. Let them pray, “Spare your people, LORD ! Don’t let your special possession become an object of mockery. Don’t let them become a joke for unbelieving foreigners who say, ‘Has the God of Israel left them?’”
Holy Bible. New Living Translation copyright© 1996, 2004, 2007, 2013 by Tyndale House Foundation. Used by permission of Tyndale House Publishers Inc., Carol Stream, Illinois 60188. All rights reserved.