Charles Ellicott Commentary 1 Samuel 25:22

"God do so unto the enemies of David, and more also, if I leave of all that pertain to him by the morning light so much as one man-child." — 1 Samuel 25:22 (ASV)

So and more also. —This is an unusual variation of the common form of imprecation, “God do so to me and more also, if, etc., etc.” The Syriac and Arabic Versions, followed by some commentators, instead of “enemies of David,” read “his servant David.” The Septuagint, as usual, boldly cuts the knot by leaving out the word of difficulty, and reads “David” simply, omitting “enemies.” But there is no doubt that the Hebrew text here is correct. The words signify David himself.

If God’s anger for the broken vow visited even David’s enemies, as distantly connected with him, how much more the guilty oath breaker himself? (This was Raschi’s explanation for a similar expression in Jonathan’s oath, 1 Samuel 20:16.) “A superstitious feeling probably lay at the root of this substitution of David’s enemies for himself, when thus invoking a curse” (Dean Payne Smith, in the Pulpit Commentary). Bishop Wordsworth here draws a good lesson on the non-obligation to keep a solemn oath, taken perhaps in a moment of undue excitement, and instances the evil example of Herod Antipas, who considered himself bound to carry out to the bitter end his rash oath to the daughter of Herodias, though it involved the death of John the Baptist, his former friend.