Hebrews 7:19

For the law made nothing perfect, but the bringing in of a better hope did; by the which we draw nigh unto God.

The law made nothing perfect in the sense that the Jewish priestly service could not bring people to perfection. Its failure was not incidental but lay in the ministration itself, which was utterly corrupt and had no connection with God's grace.

What the law could not do is accomplished by the bringing in of a better hope, which enables people to draw near to God through Christ. That nearness to God rests on Christ as high priest, who entered within the veil as the forerunner for His people.