And thus shall ye say to him that liveth in prosperity, Peace be both to thee, and peace be to thine house, and peace be unto all that thou hast. Peace be both to thee - This is the ancient form of sending greetings to a friend: Peace to Thee, peace to thy Household, and peace to all that Thou Hast. That is, May both thyself, thy family, and all that pertain unto thee, be in continual prosperity!
Perhaps David, by this salutation, wished Nabal to understand that he had acted so towards him and his property that nothing had been destroyed, and that all had been protected; see 1 Samuel 25:15-17.