The mourning in view was to find fulfillment in the exile, as indicated specifically by Lamentations (Lamentations 1:4). Israel’s religious festivals that punctuated the calendar would be denied to the people upon the devastation of Jerusalem. Nogalski sees the picture of Jerusalem inhabitants wandering rather aimlessly with no one to gather them together for cultic celebrations.
1 And yet this mourning will be followed by relief as promised by God. God’s elect people will participate in joy and thanksgiving in God’s appointed times of worship. People will rejoice, and God will be glorified.
2
18 I will gather those of you who mourn for the festival, so that you will no longer suffer reproach.