1 Samuel 20:4
20:4 Jonathan said to David, “Whatever [indicates Jonathan’s great love for David] you want me to do, I’ll do for you.”

1 Samuel 20:12-14
20:12 Then Jonathan [cf. 1 Sam. 18:1-4 re: friendship between David and Jonathan] said to David: “By the LORD, the God of Israel [Jonathan made a pledge], I will surely sound out [assess the situation] my father by this time the day after tomorrow! If he is favorably disposed toward you, will I not send you word and let you know?

20:13 But if my father is inclined to harm you, may the LORD deal with me [Jonathan made another pledge], be it ever so severely, if I do not let you know [true friends never deceive one another] and send you away safely. May the LORD be with you as he has been with my father.

20:14 But show me [Jonathan] unfailing kindness [a love that remains faithful] like that of the LORD as long as I live, so that I may not be killed [common practice for new king to kill all male members of old dynasty],

1 Samuel 20:17
20:17 And Jonathan had David reaffirm his oath [his side of the agreement] out of love for him, because he loved him as he loved himself [cf. Lev. 19:18b; Matt. 22:398; Jn. 13:34b].

1 Samuel 20:31-33
20:31 [Saul appealed to Jonathan’s ambition] As long as the son of Jesse lives on this earth, neither you [Jonathan] nor your kingdom will be established. Now send and bring him to me, for he must die!”

20:32 “Why should he be put to death? What has he done?” Jonathan asked [with courage and conviction; cf. 1 Sam. 19:4 re: Jonathan’s earlier words to Saul] his father.

20:33 But Saul hurled his spear at him [his own son] to kill him. Then Jonathan knew that his father intended to kill David.

1 Samuel 20:42
20:42 Jonathan said to David, “Go in peace, for we [emphasizes mutual nature of their friendship] have sworn [their oath would keep them united even through physical separation] friendship [cf. 1 Sam. 20:13-17] with each other in the name of the LORD, saying, ‘The LORD is witness between you and me, and between your descendants and my descendants [cf. 2 Sam. 9:3-13 re: David’s care of Mephibosheth, Jonathan’s son] forever.’” Then David left, and Jonathan went back to the town [they would only briefly meet again once more (cf. 1 Sam. 23:16-18)].