How can a young man keep his way pure? By keeping it according to Your word.
NASB95
How can a young man keep his way pure? By guarding it according to your word.
ESV
Wherewithal shall a young man cleanse his way? by taking heed thereto according to thy word.
KJV

Why is the young man so especially called to cleanse his way? Because God justly claims the first and the best. And is it not a most affecting proof of the alienation of the heart from God, that the youth of man—the bloom and freshness of his mind, "his first love"—should naturally be devoted to the service of sin? Ever since fallen man "begat a son in his own likeness," "the imagination of man's heart has been evil from his youth." For "who can bring a clean thing out of an unclean?" And never does the heart utter the cry, "My Father! You are the guide of my youth," until the misery of wandering without a guide has been painfully felt. And even when Divine grace has awakened the desire to return homewards, the habit of wandering from God, and the long-cherished pollutions of sin, seem to form an almost invincible barrier to progress.

The fearful power of "youthful lusts," and the madness with which the heart is hurried into forbidden indulgences, give solemn weight to the inquiry, "How shall a young man cleanse his way?" And the answer is ready. Let him "take heed thereto according to Your word." Thus did Joseph, and Daniel with his young companions, "cleanse their way" in the defilement of an heathen atmosphere. It was probably the recollection of this purifying efficacy of the word, that induced the venerable Beza to mention in his will, among his chief matters of thankfulness to God—the mercy of having been called to the knowledge of the truth at the age of sixteen; thus, during a course of more than seventy years' walk with God, "escaping the pollutions of the world through lust." But the "way can only be cleansed" by the cleansing of the heart; for how can a corrupt fountain "send forth" other than "bitter waters?" "Out of the heart are the issues of life." Hence the urgent need to cry, "Create in me a clean heart, O God, and renew a right spirit within me."

How precious, therefore, is the word of God, as the means of this cleansing operation! When our Savior had been setting forth Himself as "the way, the truth, and the life," and exhibiting the high privilege of union with Himself, "Now," He adds, "you are clean, through the word which I have spoken unto you." This is "the truth," which He pleaded with His Father as the means of our sanctification. This sets out our purifying hope. Here are the promises, by which we "cleanse ourselves from all filthiness of flesh and spirit, perfecting holiness in the fear of God." Thus is restored to man that golden "crown"—the stamp of his Maker's holiness—which "fell from his head when he sinned."

But oh! how does the recollection force itself upon us, that our way needs daily cleansing! so defiled are our actions, our thoughts, our motives—no more, our prayers and services. Let us then "take heed according to the word of God"—specially thankful for its heavenly light, which guides us to the "Fountain, that is opened for sin and for uncleanness." Let us also, under the same Divine light, seek for the daily sanctifying influence of the Spirit of God. "Who can understand his errors? Cleanse me from secret faults." "Cleanse the thoughts of my heart by the inspiration of Your Holy Spirit." (Prayer-Book.)

"Wherewithal shall a young man cleanse his way?" How shall he become and remain practically holy? He is but a young man, full of hot passions, and poor in knowledge and experience; how shall he get right, and keep right? Never was there a more important question for any man; never was there a fitter time for asking it than at the commencement of life. It is by no means an easy task which the prudent young man sets before himself. He wishes to choose a clean way, to be himself clean in it, to cleanse it of any foulness which may arise in the future, and to end by showing a clear course from the first step to the last; but, alas! his way is already unclean by actual sin which he has already committed, and he himself has already within his nature a tendency towards that which defiles. Here, then, is the difficulty; first, of beginning aright; next, of being always able to know and choose the right, and of continuing in the right until perfection is ultimately reached: this is hard for any man, how shall a youth accomplish it? The way, or life, of a man has to be cleansed from the sins of his youth behind him, and kept clear of the sins which temptation will place before him: this is the work, this is the difficulty.

No nobler ambition can lie before a youth, none to which he is called by so sure a calling; but none in which greater difficulties can be found. Let him not, however, shrink from the glorious enterprise of living a pure and gracious life; rather let him inquire the way by which all obstacles may be overcome. Let him not think that he knows the road to easy victory, nor dream that he can keep himself by his own wisdom; he will do well to follow the Psalmist, and become an earnest enquirer asking how he may cleanse his way. Let him become a practical disciple of the holy God, who alone can teach him how to overcome the world, the flesh, and the devil, that trinity of defilers by whom many a hopeful life has been spoiled. He is young and unaccustomed to the road, let him not be ashamed often to inquire his way of him who is so ready and so able to instruct him in it.

Our "way" is a subject which concerns us deeply, and it is far better to inquire about it than to speculate upon mysterious themes which rather puzzle than enlighten the mind. Among all the questions which a young man asks, and they are many, let this be the first and chief: "Wherewithal shall I cleanse my way?" This is a question suggested by common sense, and pressed home by daily occurrences; but it is not to be answered by unaided reason, nor, when answered, can the directions be carried out by unsupported human power. It is ours to ask the question, it is God's to give the answer and enable us to carry it out.

"By taking heed thereto according to your word."

Young man, the Bible must be your chart, and you must exercise great watchfulness that your way may be according to its directions. You must take heed to your daily life as well as study your Bible, and you must study your Bible that you may take heed to your daily life. With the greatest care a man will go astray if his map misleads him; but with the most accurate map he will still lose his road if he does not take heed to it. The narrow way was never hit upon by chance, neither did any heedless man ever lead a holy life. We can sin without thought, we have only to neglect the great salvation and ruin our souls; but to obey the Lord and walk uprightly will need all our heart and soul and mind. Let the careless remember this.

Yet the "word" is absolutely necessary; for, otherwise, care will darken into morbid anxiety, and conscientiousness may become superstition. A captain may watch from his deck all night; but if he knows nothing of the coast, and has no pilot on board, he may be carefully hastening on to shipwreck. It is not enough to desire to be right; for ignorance may make us think that we are doing God service when we are provoking him, and the fact of our ignorance will not reverse the character of our action, however much it may mitigate its criminality. Should a man carefully measure out what he believes to be a dose of useful medicine, he will die if it should turn out that he has taken up the wrong vial, and has poured out a deadly poison: the fact that he did it ignorantly will not alter the result. Even so, a young man may surround himself with ten thousand ills, by carefully using an unenlightened judgment, and refusing to receive instruction from the word of God. Willful ignorance is in itself willful sin, and the evil which comes of it is without excuse. Let each man, whether young or old, who desires to be holy have a holy watchfulness in his heart, and keep his Holy Bible before his open eye. There he will find every turn of the road marked down, every slough and miry place pointed out, with the way to go through unsoiled; and there, too, he will find light for his darkness, comfort for his weariness, and company for his loneliness, so that by its help he shall reach the blessing of the first verse of the psalm, which suggested the Psalmist's inquiry, and awakened his desires.

Note how the first section of eight verses has for its first verse, "Blessed are the undefiled in the way," and the second section runs parallel to it, with the question, "Wherewithal shall a young man cleanse his way?" The blessedness which is set before us in a conditional promise should be practically sought for in the way appointed. The Lord says, "For this will I be inquired of by the house of Israel to do it for them."

The sooner we avail ourselves of a promise of God the better, especially as our early days enjoy peculiar encouragement! for Wisdom has said, "They that seek me early shall find me." It is a pity to miss for a year, or even a day or an hour, the blessedness which belongs to holiness.