And he did that which was right in the sight of the LORD, but not with a perfect heart.
But not, … — He was not an enemy to religion, but a cool and indifferent friend. He was not a man of serious piety; for his heart was not whole with God.
 But there came a man of God to him, saying, O king, let not the army of Israel go with thee; for the LORD is not with Israel, to wit, with all the children of Ephraim.
Let not, … — It is comfortable to employ those, who we have reason to hope, have an interest in heaven, but dangerous associating with those from whom the Lord is departed.
 But if thou wilt go, do it, be strong for the battle: God shall make thee fall before the enemy: for God hath power to help, and to cast down.
Do it — It is an ironical concession like that, go, and prosper.
 Then Amaziah separated them, to wit, the army that was come to him out of Ephraim, to go home again: wherefore their anger was greatly kindled against Judah, and they returned home in great anger.
Anger kindled — Because they were both disgraced by this rejection, and disappointed of that spoil which they hoped to gain, whereas now they are sent away empty; for the hundred talents probably were given to their officers only to raise men for this service.
 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 Bethhoron, and smote three thousand of them, and took much spoil.
Cities of Judah — Thus God chastised those cities of Judah for their idolatries which were found most in the parts next to Israel. The men of Israel had corrupted them, and now are a plague to them.
 And it came to pass, as he talked with him, that the king said unto him, Art thou made of the king's counsel? forbear; why shouldest thou be smitten? Then the prophet forbare, and said, I know that God hath determined to destroy thee, because thou hast done this, and hast not hearkened unto my counsel.
Art thou, … — Who art thou that presumest to direct my affairs, without my commission? The secure sinner perhaps values himself on having silenced his reprovers and monitors. But what comes of it? It is a plain indication he is marked out for ruin. They that are deaf to reproof, are ripening apace for destruction.
 Then Amaziah king of Judah took advice, and sent to Joash, the son of Jehoahaz, the son of Jehu, king of Israel, saying, Come, let us see one another in the face.
Advice — About the injury which the Israelites had done to his people, and how he should repair it. He took advice. But with whom? Not with the prophet, but with his flattering statesmen. It is good to take advice: but it should be of them who are fit to advise us.
 But Amaziah would not hear; for it came of God, that he might deliver them into the hand of their enemies, because they sought after the gods of Edom.
Of God — Who gave him up to his own error and passion, in order to his ruin.
 And he took all the gold and the silver, and all the vessels that were found in the house of God with Obededom, and the treasures of the king's house, the hostages also, and returned to Samaria.
Obed-edom — With Obed-edom's posterity, to whom the custody of the sacred treasures was committed.