And they two made a covenant before the LORD: and David abode in the wood, and Jonathan went to his house.
ZEFANIABIBLE_BIBLE_BOOK_NAME_9 18:3
Jonathan made a covenant with David because he loved him as much as himself.
ZEFANIABIBLE_BIBLE_BOOK_NAME_9 20:12-17
12
"By the LORD, the God of Israel, if I sound out my father by this time tomorrow or the next day and I find out that he is favorable toward you, and if I do not send for you and tell you,
13
then may God punish Jonathan and do so severely. If my father intends to bring evil on you, then I will tell you, and I will send you away, and you will go in peace. May the LORD be with you, just as He was with my father.
14
If I continue to live, treat me with the LORD's faithful love, but if I die,
15
don't ever withdraw your faithful love from my household-- not even when the LORD cuts off every one of David's enemies from the face of the earth."
16
Then Jonathan made a covenant with the house of David, saying, "May the LORD hold David's enemies accountable."
17
Jonathan once again swore to David in his love for him, because he loved him as he loved himself.
ZEFANIABIBLE_BIBLE_BOOK_NAME_9 20:42-17
ZEFANIABIBLE_BIBLE_BOOK_NAME_10 9:1
David asked, "Is there anyone remaining from Saul's family I can show kindness to because of Jonathan?"
ZEFANIABIBLE_BIBLE_BOOK_NAME_10 21:7
David spared Mephibosheth, the son of Saul's son Jonathan, because of the oath of the LORD that was between David and Jonathan, Saul's son.