(21) Dwelt in Tirzah--that is, returned to his own capital: in the first instance, of course, retiring to meet the new enemy in the north, and then obliged to give up his attempt against Asa. From 1Kings 20:34, it seems as if, till the time of Ahab, Syria retained its conquests and a certain supremacy over Israel. Baasha may have had to buy peace by undertaking to leave unmolested Judah, which might be considered a tributary of Syria.

Pulpit Commentary

Verse 21. - And it came to pasta, when Baaaha heard thereof, that he left off building of Ramah [He could not prosecute it when he had enemies on every side. He at once assumes the defensive], and dwelt in Tirzah. [Ch. 14:17. He retired to his capital It is not implied that he had entertained the idea of dwelling at Ramah.]

Matthew Henry's Concise Commentary

15:9-24 Asa did what was right in the eyes of the Lord. That is right indeed which is so in God's eyes. Asa's times were times of reformation. He removed that which was evil; there reformation begins, and a great deal he found to do. When Asa found idolatry in the court, he rooted it out thence. Reformation must begin at home. Asa honours and respects his mother; he loves her well, but he loves God better. Those that have power are happy when thus they have hearts to use it well. We must not only cease to do evil, but learn to do well; not only cast away the idols of our iniquity, but dedicate ourselves and our all to God's honour and glory. Asa was cordially devoted to the service of God, his sins not arising from presumption. But his league with Benhadad arose from unbelief. Even true believers find it hard, in times of urgent danger, to trust in the Lord with all their heart. Unbelief makes way for carnal policy, and thus for one sin after another. Unbelief has often led Christians to call in the help of the Lord's enemies in their contests with their brethren; and some who once shone brightly, have thus been covered with a dark cloud towards the end of their days.

Gill's Exposition of the Entire Bible

And it came to pass, when Baasha heard thereof,.... What was doing in the northern part of his kingdom:

that he left off building of Ramah; which was the thing designed to be answered by this diversion:

and dwelt in Tirzah; in the tribe of Manasseh, nearer at hand, to observe and stop the motions of the Syrian king.

OpenBible.com