Moralists may preach, 'Unless above himself he can erect himself, how mean a thing is man'; but all the preaching in the world is of no avail. The task is an impossibility. The stream cannot rise above its source, nor be purified in its flow if bitter waters come from the fountain. 'Who can bring a clean thing out of an unclean?' There is no power in human nature to cast off this clinging self. As in the awful vision of the poet, the serpent is grown into the man. The will is feeble for good, the conscience sits like a discrowned king issuing empty mandates, while all his realm is up in rebellion and treats his proclamations as so much waste paper. How can a man re-make himself? how cast off his own nature? The means at his disposal themselves need to be cleansed, for themselves are tainted. It is the old story--who will keep the keepers?--who will heal the sick physicians? You will sometimes see a wounded animal licking its wounds with its own tongue. How much more hopeless still is our effort by our own power to stanch and heal the gashes which sin has made! 'Put off the old man'--yes--and if it but clung to the limbs like the hero's poisoned vest, it might be possible. But it is not a case of throwing aside clothing, it is stripping oneself of the very skin and flesh--and if there is nothing more to be said than such vain commonplaces of impossible duty, then we must needs abandon hope, and wear the rotting evil till we die.
But that is not all. 'What the law could not do, in that it was weak through the flesh,' God sending His own Son did--He condemned sin in the flesh. So we come to
III. The possibility of fulfilling the command.
The context tells us how this is possible. The law, the pattern, and the power for complete victory over the old sinful self, are to be found, 'as the truth is--in Jesus.' Union with Christ gives us a real possession of a new principle of life, derived from Him, and like His own. That real, perfect, immortal life, which hath no kindred with evil, and flings off pollution and decay from its pure surface, will wrestle with and finally overcome the living death of obedience to the deceitful lusts. Our weakness will be made rigorous by His inbreathed power. Our gravitation to earth and sin will be overcome by the yearning of that life to its source. An all-constraining motive will be found in love to Him who has given Himself for us. A new hope will spring as to what may be possible for us, when we see Jesus, and in Him recognise the true Man, whose image we may bear. We shall die with Him to sin, when, resting by faith on Him who has died for sin, we are made conformable to His death, that we may walk in newness of life. Faith in Jesus gives us a share in the working of that mighty power by which He makes all things new. The renovation blots out the past, and changes the direction of the future. The fountain in our hearts sends forth bitter waters that cannot be healed. 'And the Lord showed him a tree,' even that Cross whereon Christ was crucified for us, 'which, when he had cast into the waters, the waters were made sweet.'
I remember a rough parable of Luther's, grafted on an older legend, on this matter, which runs somewhat in this fashion: A man's heart is like a foul stable. Wheelbarrows and shovels are of little use, except to remove some of the surface filth, and to litter all the passages in the process. What is to be done with it? 'Turn the Elbe into it,' says he. The flood will sweep away all the pollution. Not my own efforts, but the influx of that pardoning, cleansing grace which is in Christ will wash away the accumulations of years, and the ingrained evil which has stained every part of my being. We cannot cleanse ourselves, we cannot 'put off' this old nature which has struck its roots so deep into our being; but if we turn to Him with faith and say--Forgive me, and cleanse, and strip from me the foul and ragged robe fit only for the swine-troughs in the far-off land of disobedience, He will receive us and answer all our desires, and cast around us the pure garment of His own righteousness. 'The law of the spirit of life in Christ Jesus shall make us free from the law of sin and death.'