Albert Barnes Commentary 1 Samuel 25:26

"Now therefore, my lord, as Jehovah liveth, and as thy soul liveth, seeing Jehovah hath withholden thee from bloodguiltiness, and from avenging thyself with thine own hand, now therefore let thine enemies, and them that seek evil to my lord, be as Nabal." — 1 Samuel 25:26 (ASV)

The passage should be rendered as follows: And now my lord, as the Lord liveth, and as thy soul liveth, it is the Lord that hath withholden thee from coming into blood-guiltiness (as in 1 Samuel 25:33), and from saving thyself with thine own hand; and now all thine enemies shall be as Nabal (whom she considers as utterly impotent to hurt David, and as already thoroughly humbled before him), and so shall be all that seek evil to my Lord.