After David had finished talking with Saul, Jonathan1 became one in spirit with David, and he loved2 him as himself.3
References for 1 Samuel 18:1
From that day Saul kept David with him and did not let him return to his father's house.
And Jonathan made a covenant4 with David because he loved him as himself.
References for 1 Samuel 18:3
Jonathan took off the robe5 he was wearing and gave it to David, along with his tunic, and even his sword, his bow and his belt.6
References for 1 Samuel 18:4