1 Samuel 20:8

Therefore thou shalt deal kindly with thy servant, show him merciful kindness; for thou hast brought thy servant into a covenant of the Lord with thee; it was on the basis of this covenant of friendship that David appealed to Jonathan. Notwithstanding, if there be in me iniquity, slay me thyself, in case of a trespass on his part, he would rather die by the hand of his friend; for why shouldest thou bring me to thy father?