While King Saul is still in power, David is anointed king. 1 Samuel 16.
Then the Spirit of the LORD departed from Saul.
1 Samuel 17 describes the battle between David and the Philistine giant Goliath. The victory over Goliath puts David in the center of attention.
Saul takes him and appoints him to the royal court.
Jonathan, the son of Saul, recognizes in David the heroic action in the Name of the LORD against the enemy. He himself previously defeated twenty Philistines together with his armor bearer, with God's help. 1 Samuel 14.
David and Jonathan show great courage of faith in their actions.
After David's appointment to Saul's court, Jonathan becomes intimately connected to David; a close friendship develops, and they enter into a covenant of friendship.
As a sign of this covenant, Jonathan gives David his clothing, sword, bow and belt. Jonathan hereby transfers the signs of his royal dignity as crown prince to David. Later Jonathan will recognize that the kingship belongs to David. See 1 Samuel 20 verses 13 to 17 and 1 Samuel 23 verse 17. In these verses friendship is confirmed by invoking God's Name.
Jonathan offers space to God's anointed successor to Saul.
This action of Jonathan foreshadows the love and great friendship of Jesus, the Son of God, the King of heaven and earth:
-The king's son Jonathan is not ashamed to make friends with a shepherd boy. Likewise Jesus: He “is not ashamed to call them (us) brethren.” Hebrews 2 verse 11.
-Jonathan's soul was devoted to David. Likewise Jesus: “His own whom he loved, he loved to the end.” John 13 verse 1.
-Jonathan made an everlasting covenant with David. 1 Samuel 20 verse 42. Likewise Jesus: He has made the new covenant with us. Matthew 26 verse 28.
-Jonathan took off his cloak and gave David his clothes, and even his armor. Likewise Jesus: He stripped Himself of His glory. He has clothed us with the robe of His righteousness, and has armed and girded us for the fight of faith.
-Jonathan gave David strength in his weakness. So too Jesus:
“My grace is sufficient for you, for My power is made perfect in weakness.” 2 Corinthians 12 verse 9.
-Jonathan mediated between his father and David, even though he himself was in danger. Likewise Jesus: 'For there is one God. There is also one Mediator between God and men, the man Christ Jesus.