1 Samuel 19:3-5

I will stand by my father in the field In which it is likely Saul used to walk in the morning and take the fresh air. Thereabouts he advised David to lurk in some secret place; that he might speedily acquaint him with the issue of his discourse with his father, 1 Samuel 19:4. Jonathan spake good of David unto Saul Which he could not do without hazard to himself. Herein, therefore, he performed the duty of a true friend and of a valiant man. He put his life in his hand Or, in the greatest hazard: And slew the Philistine He puts him in mind of that hazardous enterprise wherein he slew Goliath; in which David did indeed hazard his life greatly, for had he missed with his sling he must certainly have been slain.