Which prophet persuaded Israel's army to release the captives taken from Judah?

Answer: Oded

In Ahaz's reign Oded warned Israel's army returning to Samaria; the captives were clothed, fed and brought to Jericho.

“But a prophet of the LORD named Oded was there, and he went out to meet the army that returned to Samaria. “Look,” he said to them, “because of His wrath against Judah, the LORD, the God of your fathers, has delivered them into your hand. But you have slaughtered them in a rage that reaches up to heaven.”— 2 Chronicles 28:9 (BSB)