The testimony, i.e. the book of the law, which he put into the king's hand, to mind him of his duty at his entrance upon his kingdom, which was to read and write out that holy book, Deuteronomy 17:18, and to govern himself and his kingdom by it; the law of God being frequently and most properly called a testimony, as Psalms 78:5, Psalms 132:12 Isaiah 8:16,20; see also Deuteronomy 6:17,20 2 Kings 23:3, because it is a witness of God's will, and man's duty. Anointed him; as they used to do in doubtful cases, when there was any competition or question about the crown, as now there was.
Related Commentaries of 2 Kings 11:12
2 Kings 11:12
12 And he brought forth the king's son, and put the crown upon him, and gave him the testimony; and they made him king, and anointed him; and they clapped their hands, and said, God save the king.