Passage
And when they began to sing and to praise, Jehovah set liers-in-wait against the children of Ammon, Moab, and mount Seir, that were come against Judah; and they were smitten.
And when they began to sing and to praise, Jehovah set liers-in-wait against the children of Ammon, Moab, and mount Seir, that were come against Judah; and they were smitten.
2 Chronicles 20:20 And they rose early in the morning, and went forth into the wilderness of Tekoa: and as they went forth, Jehoshaphat stood and said, Hear me, O Judah, and ye inhabitants of Jerusalem: believe in Jehovah your God, so shall ye be established; believe his prophets, so shall ye prosper.
2 Chronicles 20:21 And when he had taken counsel with the people, he appointed them that should sing unto Jehovah, and give praise in holy array, as they went out before the army, and say, Give thanks unto Jehovah; for his lovingkindness [endureth] for ever.
2 Chronicles 20:22 And when they began to sing and to praise, Jehovah set liers-in-wait against the children of Ammon, Moab, and mount Seir, that were come against Judah; and they were smitten.
2 Chronicles 20:23 For the children of Ammon and Moab stood up against the inhabitants of mount Seir, utterly to slay and destroy them: and when they had made an end of the inhabitants of Seir, every one helped to destroy another.
2 Chronicles 20:24 And when Judah came to the watch-tower of the wilderness, they looked upon the multitude; and, behold, they were dead bodies fallen to the earth, and there were none that escaped.
The verse centers on "began", "sing", "praise", "jehovah", "liers-in-wait", "against", "children", and "ammon". It is saying that the verse draws attention to "began" and "sing", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 21's "And when he had taken counsel with..." into verse 23's "For the children of Ammon and Moab...", so "began" and "sing" 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 "began" and "sing" with trust shaped by these words, not by a vague optimism outside the passage.