Natural or Unnatural?

1 Samuel 18:1-4 (NKJV)
Now when he had finished speaking to Saul, the soul of Jonathan was knit to the soul of David, and Jonathan loved him as his own soul. 2 Saul took him that day, and would not let him go home to his father’s house anymore. 3 Then Jonathan and David made a covenant, because he loved him as his own soul. 4 And Jonathan took off the robe that was on him and gave it to David, with his armor, even to his sword and his bow and his belt.