1 Samuel 19:4-6 (KJV)
4 And Jonathan spake good of David unto Saul his father, and said unto him, Let not the king sin against his servant, against David; because he hath not sinned against thee, and because his works have been to thee-ward very good:
5 For he did put his life in his hand, and slew the Philistine, and the Lord wrought a great salvation for all Israel: thou sawest it, and didst rejoice: wherefore then wilt thou sin against innocent blood, to slay David without a cause?
6 And Saul hearkened unto the voice of Jonathan: and Saul sware, As the Lord liveth, he shall not be slain.
1 Samuel 19
David Fled From Saul
If it wasn’t for Jonathan, that night, Saul may have tried early on to kill David. So thankfully his son at least saw the good in David and had his back, along with God, of course.