1 Samuel 18:3

3 And Jonathan maketh -- also David -- a covenant, because he loveth him as his own soul,

1 Samuel 18:3 Meaning and Commentary

1 Samuel 18:3

Then Jonathan and David made a covenant
A covenant of friendship; entered into a solemn agreement to keep up and maintain a cordial respect to each other, and to support each other's interest both in life and after death, whoever was the survivor; and in consequence of this David had a friend at court, when Saul fell out with him, and who pleaded his cause, and discovered his father's plots, and was the means of preserving David's life:

because he loved him as his own soul;
so that this covenant was not founded in mere words, but in sincere and cordial affection, and was lasting and inviolable.

1 Samuel 18:3 In-Context

1 And it cometh to pass, when he finisheth to speak unto Saul, that the soul of Jonathan hath been bound to the soul of David, and Jonathan loveth him as his own soul.
2 And Saul taketh him on that day, and hath not permitted him to turn back to the house of his father.
3 And Jonathan maketh -- also David -- a covenant, because he loveth him as his own soul,
4 and Jonathan strippeth himself of the upper robe which [is] upon him, and giveth it to David, and his long robe, even unto his sword, and unto his bow, and unto his girdle.
5 And David goeth out whithersoever Saul doth send him; he acted wisely, and Saul setteth him over the men of war, and it is good in the eyes of all the people, and also in the eyes of the servants of Saul.
Young's Literal Translation is in the public domain.