And sin must be furthermore recognized as a concrete or personal fact. It is not enough to acknowledge the incontrovertible presence of sin in the world around us. The important thing is, that this sin inheres in me. So David prayed, "Have mercy upon me, O God, according unto thy loving kindness; for I have sinned and done this evil in thy sight." He had always known, in general terms, that adultery was a fearful thing; but when it pointed its gaunt finger at him in the watches of the night and hissed, "Bathsheba!" it brought him to his knees.
And this conviction of sin must be followed by a resolution to forsake it. The true penitent fears his sin, hates it, loathes it, abhors it, and determines to quit it.
But observe, all this is merely preliminary to the one thing needful. There is no virtue in repentance per se. The penitent is not saved; he has only discovered his need of salvation. He knows his malady; now how shall he be cured of it? To pause here is death. One in a sinking boat must not be satisfied with stopping the leak; the boat must be baled out. A man head over ears in debt can not recover his credit by resolving to pay cash in the future; he must somehow cancel his past obligations. If a penitent were never to commit another sin, the "handwriting of ordinances" would still be against him. The record of the past remains; and it will confront him in the judgment unless it be disposed of. The past. The mislived past! What shall be done about it?
This brings us to the matter in hand: What shall I do to be saved? or How shall I become a Christian?
Our Lord at the beginning of His ministry said to Nicodemus, "God so loved the world, that he gave his only begotten Son, that whosoever believeth on him, should not perish, but have everlasting life." And to make the matter perfectly clear to this learned rabbi, He resorted to the kindergarten method, using an object-lesson: "As Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up (that is, crucified), that whosoever believeth in him should not perish, but have eternal life." So the one thing needful is to believe in Christ.
The same truth was repeated over and over in the teachings of Jesus and of His disciples as well. To the jailer of Philippi who, in sudden conviction, was moved to cry, "What shall I do?" the answer of Paul was, "Believe on the Lord Jesus Christ and thou shalt be saved."
But what is it to "believe in Christ?" It is easy to say, "Come to Christ" and "Accept Christ" and "Believe in Him"; but just here occurs the bewilderment. These are oftentimes mere shop-worn phrases to the unsaved, however simple they may appear to those who have entered on the Christian life.
To believe in Christ is, first, to credit the historic record of His life. Once on a time He lived among men, preached, wrought miracles, suffered and died on the accurst tree. So far all will agree; but there is clearly no saving virtue in an intellectual acceptance of an undisputed fact.
It means, second, to believe that Jesus was what He claimed to be. And His claim is perfectly clear. To the woman of Samaria who sighed for the coming of Messiah He said, "I that speak unto thee am he." No reader of the Scripture could misunderstand His meaning, since the prophecy of the Messiah runs like a golden thread through all its pages from the protevangel, "The seed of the woman shall bruise the serpent's head," to the prediction of Malachi, "The Sun of righteousness shall arise with healing in his beams."