Matthew Henry on 1 Samuel 18:6-11

David's troubles not only immediately follow his triumphs, but arise from them; such is the vanity of that which seems greatest in this world. It is a sign that the Spirit of God is departed from men, if, like Saul, they are peevish, envious, suspicious, and ill-natured. Compare David, with his harp in his hand, aiming to serve Saul, and Saul, with his javelin in his hand, aiming to slay David; and observe the sweetness and usefulness of God's persecuted people, and the barbarity of their persecutors. But David's safety must be ascribed to God's providence.