It is our duty to be “perfecting holiness in the fear of God,” 2 Cor. 7:1; to be “growing in grace” every day, 1 Pet. 2:2, 2 Pet. 3:18; to be “renewing our inward man day by day,” 2 Cor. 4:16. Now, this cannot be done without the daily mortifying of sin. Sin sets its strength against every act of holiness, and against every degree we grow to. Let not that man think he makes any progress in holiness who walks not over the bellies of his lusts. He who doth not kill sin in his way takes no steps towards his journey’s end. He who finds not opposition from it, and who sets not himself in every particular to its mortification, is at peace with it, not dying to it.
The law can bring forth no righteousness, no obedience; it is weak to any such purpose, by reason of the flesh, and that corruption that is come on us. These two things are done in Christ, and by him:—First, Sin is condemned as to its guilt, and we set free from that; the righteousness of the law by his obedience is fulfilled in us, who could never do it ourselves. And, secondly, That obedience which is required of us, his Spirit works it in us. So that that perfection of obedience which we have in him is imputed to us; and the sincerity that we have in obedience is from his Spirit bestowed on us. And this is the most excellent glass, wherein we see our impotency; for what need we his perfect obedience to be made ours, but that we have not, can not attain any? what need we his Spirit of life to quicken us, but that we are dead in trespasses and sins?