1 Samuel 18:3,4
Then Jonathan and David made a covenant, because he loved him as his own soul.
Nave's Topical Index—AKJV

1 Samuel 20:16,42
So Jonathan made a covenant with the house of David, saying, Let the LORD even require it at the hand of David's enemies.
Nave's Topical Index—AKJV

2 Samuel 21:7
But the king spared Mephibosheth, the son of Jonathan the son of Saul, because of the LORD's oath that was between them, between David and Jonathan the son of Saul.
Nave's Topical Index—AKJV