No believer can of himself act,—that is, actually exert or exercise,—this principle or power of a spiritual life, in any one instance of any duty, internal or external, towards God or men, so as that it shall be an act of holiness, or a duty accepted with God. He cannot, I say, do so of himself, by virtue of any power habitually inherent in him. We are not in this world intrusted with any such spiritual ability from God, as without farther actual aid and assistance to do any thing that is good.