2 Chronicles 25:13
But the soldiers of the army which Amaziah sent back, that they should not go with him to battle, fell upon the cities of Judah, from Samaria even unto Beth-horon, and smote three thousand of them, and took much spoil. But the soldiers of the army which Amaziah sent back, that they should not go with him to battle, fell upon the cities of Judah, from Samaria even unto Beth-horon, and smote three thousand of them, and took much spoil.
The verse belongs to the reign of Amaziah, the disloyal and unstable king of Judah, who followed Joash, who was good as long as Jehoiada the priest lived, and who was followed by Azariah, also called Uzziah, a great king. It falls together with 2 Chronicles 25 and 26 within 2 Chronicles 23 to 32 for Monday May 13. It belongs to Amaziah's warfare against Edom, when he dismissed the hired Israelite troops he had paid for and would not let them go with him to battle.
The verse records the harm that followed that dismissal, in that the dismissed soldiers fell upon the cities of Judah from Samaria even unto Beth-horon, smote three thousand of them, and took much spoil. In that warfare Israel subdued the Edomites by military force but gained no moral influence over them. Doing duty brings blessing while departing from God brings strife and captivity and great loss, and things would have been different if men had remembered God. Yet God is willing to turn to help His people when they seek Him with all the heart and works mightily for them.
Sunk costs should not keep one on a wrong course, for Amaziah feared losing the hundred talents he had paid, yet trusted God's counsel, won the battle without Israel, and learned that God's blessing is worth more than earthly riches. The wider account warns against following one's own counsel instead of accepting the Lord's prophetic counsel, since Amaziah accepted a prophet's testimony when it suited him but rejected the prophet's reproof.