Jamieson, Fausset and Brown on Hebrews 7:19

19. For, &c.--justifying his calling the law weak and unprofitable (He 7:18). The law could not bring men to: true justification or sanctification before God, which is the "perfection" that we all need in order to be accepted of Him, and which we have in Christ.

nothing--not merely "no one," but "nothing." The law brought nothing to its perfected end; everything in it was introductory to its antitype in the Christian economy, which realizes the perfection contemplated; compare "unprofitableness," He 7:18.

did--rather connect with He 7:18, thus, "There takes place (by virtue of Psa 110:4) a repealing of the commandment (on the one hand), but (on the other) a bringing in afterwards (the Greek expresses that there is a bringing in of something over and above the law; a superinducing, or accession of something new, namely, something better than the good things which the pre-existing law promised [Wahl]) of a better hope," not one weak and unprofitable, but, as elsewhere the Christian dispensation is called, "everlasting," "true," "the second," "more excellent," "different," "living," "new," "to come," "perfect." Compare He 8:6, bringing us near to God, now in spirit, hereafter both in spirit and in body.

we draw nigh unto God--the sure token of "perfection." Weakness is the opposite of this filial confidence of access. The access through the legal sacrifices was only symbolical and through the medium of a priest; that through Christ is immediate, perfect, and spiritual.