And when he had consulted with the people, and appoynted singers vnto the Lord, and them that should prayse him that is in the beautifull Sanctuarie, in going forth before the men of armes, and saying, Prayse ye the Lord, for his mercy lasteth for euer,
2 Chronicles 20:19 And the Leuites of the children of the Kohathites and of the childre of the Corhites stood vp to prayse the Lord God of Israel with a loude voyce on hie.
2 Chronicles 20:20 And when they arose early in the morning, they went forth to the wildernesse of Tekoa: and as they departed, Iehoshaphat stoode and sayde, Heare ye me, O Iudah, and ye inhabitants of Ierusalem: put your trust in the Lord your God, and ye shalbe assured: beleeue his Prophets, and ye shall prosper.
2 Chronicles 20:21 And when he had consulted with the people, and appoynted singers vnto the Lord, and them that should prayse him that is in the beautifull Sanctuarie, in going forth before the men of armes, and saying, Prayse ye the Lord, for his mercy lasteth for euer,
2 Chronicles 20:22 And when they began to shoute, and to prayse, the Lord layed ambushments against the children of Ammon, Moab, and mount Seir, which were come against Iudah, and they slewe one another.
2 Chronicles 20:23 For the children of Ammon and Moab rose against the inhabitants of mount Seir, to slay and to destroy them and when they had made an end of the inhabitantes of Seir, euery one helped to destroy another.
The verse centers on "mercy", "consulted", "people", "appoynted", "singers", "vnto", "lord", and "should". It is saying that the verse draws attention to "mercy" and "consulted", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 20's "And when they arose early in the..." into verse 22's "And when they began to shoute and...", so "mercy" and "consulted" 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 "mercy" and "consulted" with trust shaped by these words, not by a vague optimism outside the passage.