Holiness necessary from the commands of God

Although God in them requires universal holiness of us, yet he does not do it in that strict and rigorous way as by the law, so as that if we fail in any thing, either as to the matter or manner of its performance, in the substance of it or as to the degrees of its perfection, that thereon both that and all we do besides should be rejected. But he does it with a contemperation of grace and mercy, so as that if there be a universal sincerity, in a respect to all his commands, he both pardons many sins, and accepts of what we do, though it come short of legal perfection; both on the account of the mediation of Christ.