Adam Clarke on 1 Samuel 18:1

When he had made an end of speaking - These first five verses are omitted by the Septuagint. See the notes on the preceding chapter, 1 Samuel 17 (note).

Jonathan loved him as his own soul - The most intimate friendship subsisted between them; and they loved each other with pure hearts fervently. No love was lost between them; each was worthy of the other. They had a friendship which could not be affected with changes or chances, and which exemplified all that the ancients have said on the subject; Την φιλιαν ισοτητα ειναι, και μιαν ψυχην, τον φιλον ἑτερον αυτον; "Friendship produces an entire sameness; it is one soul in two bodies: a friend is another self."