This fourth call for communal lamentation ends with the command to the priests to gather the community for that lament.
Sanctify a fast renders a Hebrew expression for setting aside for God a time of fasting. Good News Translation says “Give orders for a fast.” We may also say “Set aside for God a fast [or, time of fasting].” A fast is a period during which a person will not eat, or will abstain from certain foods, for religious purposes such as sorrow for sin, or for mourning. In this case the entire community is to participate in the fast. Some languages translate this line as “Abstain from food to mourn.”
Call a solemn assembly means that the priests are to gather the whole community into one place, most likely the Temple area. Solemn assembly renders a single word in Hebrew referring to a gathering of all the people. Good News Translation simply says “assembly,” but it is better to say “religious [or, special] assembly.” The whole line may be translated “call the people together for a religious meeting” or “… to worship God.”
Gather the elders and all the inhabitants of the land: The elders and all the inhabitants of the land are “the leaders and the rest of the people of Judah” (similarly Good News Translation). See the discussion of these terms in Joel 1.2. The Hebrew of these two lines can be understood as a command to the elders to gather the people together, but the full context makes it more likely that it is the priests who are to gather everyone, since verses 13-14 addressed to the priests. It is not certain whether the entire population of Judah would have gathered at the Temple, or only certain representatives of the families. However, in postexilic times the population was relatively small, and it is possible that all the people came who were able.
The house of the LORD your God is “the Temple” (Good News Translation). The building itself was not used for such an assembly, but the area or courtyard around the Temple. The entire space was frequently referred to as “the house of the LORD.” When the prophet refers to the LORD your God, he is not denying that Yahweh is his own God as well. But he is emphasizing the responsibility of the people to recognize their own relationship with God.
Cry to the LORD is a command to speak the lament with a loud voice. It may be rendered “cry out your misery to Yahweh” or “cry out to Yahweh for help.”
Quoted with permission from de Blois, Kees & Dorn, Louis. A Handbook on Joel. (UBS Helps for Translators). Miami: UBS, 2020. For this and other handbooks for translators see here .