*Minor differences ignored. Grouped by changes, with first version listed as example.
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.
Then Jonathan and David made a covenant--Such covenants of brotherhood are frequent in the East. They are ratified by certain ceremonies, and in presence of witnesses, that the persons covenanting will be sworn brothers for life.
Jonathan made a covenant (i.e., a covenant of friendship) and (i.e., with) David, because he loved him as his soul.
*More commentary available at chapter level.