And it shall come to pass in that day, that the mountains shall drop down new wine, and the hills shall flow with milk, and all the rivers of Judah shall flow with waters, and a fountain shall come forth of the house of the LORD, and shall water the valley of Shittim.
Joel 3:16 The LORD also shall roar out of Zion, and utter his voice from Jerusalem; and the heavens and the earth shall shake: but the LORD will be the hope of his people, and the strength of the children of Israel.
Joel 3:17 So shall ye know that I am the LORD your God dwelling in Zion, my holy mountain: then shall Jerusalem be holy, and there shall no strangers pass through her any more.
Joel 3:18 And it shall come to pass in that day, that the mountains shall drop down new wine, and the hills shall flow with milk, and all the rivers of Judah shall flow with waters, and a fountain shall come forth of the house of the LORD, and shall water the valley of Shittim.
Joel 3:19 Egypt shall be a desolation, and Edom shall be a desolate wilderness, for the violence against the children of Judah, because they have shed innocent blood in their land.
Joel 3:20 But Judah shall dwell for ever, and Jerusalem from generation to generation.
The verse centers on "shall", "come", "pass", "mountains", "drop", "down", and "wine". It is saying that the verse draws attention to "shall" and "come", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 17's "So shall ye know that I am..." into verse 19's "Egypt shall be a desolation and Edom...", so "shall" and "come" belong inside that flow. In Joel context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "shall" and "come" with trust shaped by these words, not by a vague optimism outside the passage.