Though we are commanded to 'wash ourselves', to 'cleanse ourselves from sins', to 'purge ourselves from all our iniquities', yet to imagine that we can do these things by our own efforts is to trample on the cross and grace of Jesus Christ. Whatever God works in us by his grace, he commands us to do as our duty. God works all in us and by us.

By faith ponder on this, that though thou art no way able in or by thyself to get the conquest over thy distemper, though thou art even weary of contending, and art utterly ready to faint, yet that there is enough in Jesus Christ to yield thee relief...

There neither is, nor ever was, in the world, nor ever shall be, the least dram of holiness, but what, flowing from Jesus Christ, is communicated by the Spirit, according to the truth and promise of the gospel.

To suppose that whatever God requireth of us that we have power of ourselves to do, is to make the cross and grace of Jesus Christ of none effect.