Passage
To-morrow go ye down against them: behold, they come up by the ascent of Ziz; and ye shall find them at the end of the valley, before the wilderness of Jeruel.
To-morrow go ye down against them: behold, they come up by the ascent of Ziz; and ye shall find them at the end of the valley, before the wilderness of Jeruel.
2 Chronicles 20:14 Then upon Jahaziel the son of Zechariah, the son of Benaiah, the son of Jeiel, the son of Mattaniah, the Levite, of the sons of Asaph, came the Spirit of Jehovah in the midst of the assembly;
2 Chronicles 20:15 and he said, Hearken ye, all Judah, and ye inhabitants of Jerusalem, and thou king Jehoshaphat: Thus saith Jehovah unto you, Fear not ye, neither be dismayed by reason of this great multitude; for the battle is not yours, but God`s.
2 Chronicles 20:16 To-morrow go ye down against them: behold, they come up by the ascent of Ziz; and ye shall find them at the end of the valley, before the wilderness of Jeruel.
2 Chronicles 20:17 Ye shall not need to fight in this [battle]: set yourselves, stand ye still, and see the salvation of Jehovah with you, O Judah and Jerusalem; fear not, nor be dismayed: to-morrow go out against them: for Jehovah is with you.
2 Chronicles 20:18 And Jehoshaphat bowed his head with his face to the ground; and all Judah and the inhabitants of Jerusalem fell down before Jehovah, worshipping Jehovah.
The verse centers on "to-morrow", "down", "against", "behold", "come", "ascent", "shall", and "find". It is saying that the verse draws attention to "to-morrow" and "down", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 15's "and he said Hearken ye all Judah..." into verse 17's "Ye shall not need to fight in...", so "to-morrow" and "down" belong inside that flow. In 2 Chronicles context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "to-morrow" and "down" with trust shaped by these words, not by a vague optimism outside the passage.