19. "Wherefore then serveth the law?" as it is of no avail for justification, is it either useless, or contrary to the covenant of God? [CALVIN].
      added--to the original covenant of promise. This is not inconsistent with Ga 3:15, "No man addeth thereto"; for there the kind of addition meant, and therefore denied, is one that would add new conditions, inconsistent with the grace of the covenant of promise. The law, though misunderstood by the Judaizers as doing so, was really added for a different purpose, namely, "because of (or as the Greek, 'for the sake of') the transgressions," that is, to bring out into clearer view the transgressions of it (Ro 7:7-9); to make men more fully conscious of their "sins," by being perceived as transgressions of the law, and so to make them long for the promised Saviour. This accords with Ga 3:23, 24; Ro 4:15. The meaning can hardly be "to check transgressions," for the law rather stimulates the corrupt heart to disobey it (Ro 5:20; 7:13).
      till the seed--during the period up to the time when the seed came. The law was a preparatory dispensation for the Jewish nation (Ro 5:20; Greek, "the law came in additionally and incidentally"), intervening between the promise and its fulfilment in Christ.
      come--(Compare "faith came," Ga 3:23).
      the promise-- (Ro 4:21).
      ordained--Greek, "constituted" or "disposed."
      by angels--as the instrumental enactors of the law [ALFORD] God delegated the law to angels as something rather alien to Him and severe (Ac 7:53; Heb 2:2, 3; compare De 33:2, "He came with ten thousands of saints," that is, angels, Ps 68:17). He reserved "the promise" to Himself and dispensed it according to His own goodness.
      in the hand of a mediator--namely, Moses. De 5:5, "I stood between the Lord and you": the very definition of a mediator. Hence the phrase often recurs, "By the hand of Moses." In the giving of the law, the "angels" were representatives of God; Moses, as mediator, represented the people.

JFB.