Jamieson, Fausset and Brown on 1 Samuel 15:12

12. Saul came to Carmel--in the south of Judah (Jos 15:55; 1Sa 25:2).

he set him up a place--that is, a pillar (2Sa 18:18); literally, a hand, indicating that whatever was the form of the monument, it was surmounted, according to the ancient fashion, by the figure of a hand, the symbol of power and energy. The erection of this vainglorious trophy was an additional act of disobedience. His pride had overborne his sense of duty in first raising this monument to his own honor, and then going to Gilgal to offer sacrifice to God.