C. F. Keil and Franz Delitzsch on 2 Kings 11:12

2Ki 11:12

After the approaches to the temple had all been occupied in this manner, Jehoiada brought out the king’s son from his home in the temple; or, he brought him forth, set the crown upon him, and handed him the testimony, i.e., the book of the law, as the rule of his life and action as king, according to the precept in Deu 17:18-19. ואת־העדוּת is connected with את־הנּזר עליו יתּן, because עליו יתּן has the general meaning “delivered to him, handed him,” and does not specially affirm the putting on of the crown. ימליכוּ, they made him king. The subject is the persons present, through, as a matter of course, the anointing was performed by Jehoiada and the priests, as the Chronicles expressly affirm. Clapping the hands was a sign of joyful acclamation, like the cry, “Long live the king” (cf. 1Ki 1:39).