Why then was the law given? It was added because of transgressions, until the arrival of the seed to whom the promise referred. It was administered through angels by a mediator.
KJV
Wherefore then [serveth] the law? It was added because of transgressions, till the seed should come to whom the promise was made; [and it was] ordained by angels in the hand of a mediator.
ASV
What then is the law? It was added because of transgressions, till the seed should come to whom the promise hath been made; and it was ordained through angels by the hand of a mediator.