181 Now after David's talk with Saul was ended, the soul of Jonathan was joined with the soul of David, and David became as dear to him as his very life. 2 And that day Saul took David and would not let him go back to his father's house. 3 Then Jonathan and David made an agreement together, because of Jonathan's love for David. 4 And Jonathan took off the robe he had on and gave it to David, with all his military dress, even to his sword and his bow and the band round his body. 5 And David went wherever Saul sent him, and did wisely: and Saul put him at the head of his men of war, and this was pleasing to all the people as well as to Saul's servants.
Matthew Henry's Commentary on 1 Samuel 18:1-5
Commentary on 1 Samuel 18:1-5
(Read 1 Samuel 18:1-5)
The friendship of David and Jonathan was the effect of Divine grace, which produces in true believers one heart and one soul, and causes them to love each other. This union of souls is from partaking in the Spirit of Christ. Where God unites hearts, carnal matters are too weak to separate them. Those who love Christ as their own souls, will be willing to join themselves to him in an everlasting covenant. It was certainly a great proof of the power of God's grace in David, that he was able to bear all this respect and honour, without being lifted up above measure.