9. Wherewith shall a young man cleanse his way? In this place he repeats, in different words, the same truth which he formerly advanced, That, however much men may pique themselves upon their own works, there is nothing pure in their life until they have made a complete surrender of themselves to the word of the Lord. The more effectually to excite them to this, he produces, in an especial manner, the example of children or youths. In mentioning these, he by no means gives an unbridled license to those who have arrived at mature years, or who are aged, as if they were competent to regulate their own life, and as if their own prudence served as a law to them; but because youth puts men where two ways meet, and renders it imperative for them to select the course of life which they mean to follow, he declares that, when a person sets about the regulation of his life, no advice will prove of any advantage, unless he adopts the law of God as his rule and guide. In this way the prophet stimulates men to an early and seasonable regulation of their manners, and not to delay doing so any longer, agreeably to the words of Solomon, "Remember thy Creator in thy youth, ere the days of trouble come, and the years which shall be grief unto thee," Ecclesiastes 12:1. ² They who defer from time to time become hardened in their vicious practices, and arrive at mature years, when it is too late to attempt a reformation. There is another reason, arising from the fact, of the carnal propensities being very powerful in youth, requiring a dortble restraint; and the more they are inclined to excess, the greater is the necessity for curbing their licentiousness. The prophet, therefore, not without reason, exhorts them particularly to attend to the observance of the law. We may reason from the greater to the less; for if the law of God possesses the power of restraining the impetuosity of youth, so as to preserve pure and upright all who take it for their guide, then, assuredly, when they come to maturity, and their irregular desires are considerably abated, it will prove the best antidote for correcting their vices. The reason, therefore, of so much evil prevailing in the world, arises from men wallowing in their own impurity, and being disposed to yield more to their own inclination than to heavenly instruction. The only sure protection is, to regulate ourselves according to God's word. Some, wise in their own conceit, throw themselves into the snares of Satan, others, from listlessness and languor, live a vile and wicked life.

10. With my whole heart. Conscious of the integrity of his heart, the prophet still implores the help of God, that he might not stumble by reason of his infirmity. He makes no boast of self-preparation, as if he had spontaneously begun to inquire after God, but in praising the grace which he had experienced, he at the same time aspires after steadfastness to persevere in walking in his ways. It is folly on the part of the Papists to seize upon this and similar passages, as if the saints, of their own free will, anticipated the grace of the Holy Spirit, and afterwards were favored with his aid. The prophet does not make a division between God and himself, but rather prays God to continue his work till it is completed, agreeably with what we are generally taught, to keep God mindful of his benefits until he accomplish them.

In the meantime, there is good cause for presenting our supplication to God, to stretch out his hand towards us when he sees our minds so settled, that we are solicitous of nothing so much as acting uprightly. And as he elevates us with confidence to ask the gift of perseverance, when he inspires our hearts with proper affection towards him, so also does he entreat us for the future not to sink into a careless and languid state like soldiers who have been discharged, but seek to be constantly directed by the spirit of wisdom, and to be sustained by the principles of fortitude and virtue. David here, from his own example, points out to us a rule, that by how much a man finds himself succored by God, by so much ought he to be induced the more carefully and earnestly to implore the continuance of his aid; for unless he restrain us, we will instantly wander and go astray. This sentiment is more explicitly stated in the original word yngst, tashqeni, which is in the passive voice, and signifies, to be led astray. ³ From the import of the term, I do not mean to establish the doctrine that God secretly incites us to commit sin, but only to let my readers know, that such is our liability to err, that we immediately relapse into sin the instant he leaves us to ourselves. This passage also admonishes us that the man who swerves but a little from God's commandments is guilty of going astray.

11. I have hid thy word in my heart. This psalm not being composed for the personal and peculiar use of the author only, we may therefore understand, that as frequently as David sets before us his own example, under this model he points out the course we ought to pursue. Here we are informed that we are well fortified against the stratagems of Satan when God's law is deeply seated in our hearts. For unless it have a fast and firm hold there, we will readily fall into sin. Among scholars, those whose knowledge is confined to books, if they have not the book always before them, readily discover their ignorance; in like manner, if we do not imbibe the doctrine of God, and are well acquainted with it, Satan will easily surprise and entangle us in his meshes. Our true safeguard, then, lies not in a slender knowledge of his law, or in a careless perusal of it, but in hiding it deeply in our hearts. Here we are reminded, that however men may be convinced of their own wisdom, they are yet destitute of all right judgment, except as far as they have God as their teacher.

12. Blessed art thou, O Jehovah! Such had been the prophet's proficiency, that he was not only one of 'God's disciples, but also a public teacher of the Church. Nevertheless, acknowledging himself and all the upright to be only one their journey till they arrive at the close of life, he fails not to ask for the spirit of understanding. This passage informs us generally, that if God do not enlighten us with the spirit of discernment, we are not competent to behold the light which shines forth from his law, though it be constantly before us. And thus it happens, that not a few are blind even when surrounded with the clear revelation of this doctrine, because, confident in their own perspicacity, they contemn the internal illumination of the Holy Spirit. Farther, let us learn from this passage, that none are possessed of such superiority of intellect as not to admit of constant increase. If the prophet, upon whom God had conferred so honorable an office as a teacher of the Church, confesses himself to be only a disciple or scholar, what madness is it for those who are, greatly behind him in point of attainments not to strain every nerve to rise to higher excellence? Nor does he depend upon his own merits for obtaining his requests; he beseeches God to grant them from a regard to his own glory. This appears from the phraseology by which he introduces his request, Blessed art thou, O Jehovah! intimating, that his confidence of success originated in God's being fully entitled to all praise on account of his unbounded goodness, justice, and mercy.

13. With my lips. In this verse he declares that the law of God was not only deeply engraven on his own heart, but that it was his earnest and strenuous endeavor to gain over many of his fellow-disciples into subjection to God. It is indeed a heartless matter to speak of the law of God abstractly, as we see hypocrites do, who talk very fluently about the whole doctrine of godliness, to which they are entire strangers. What the prophet noticed above, respecting the affection of the heart for God's law, he now likewise applies to the lips. And, immediately afterwards, he again establishes the truth of what he had asserted about his cordial and unfeigned endeavors to instruct others; by saying, that he derived no less pleasure from the doctrine of God than from all the riches of the world. He indirectly contrasts his holy love for the law, with which he was inflamed, with the unholy avarice which has taken possession of almost all the world. "As wealth attracts to itself the hearts of mankind, so I have taken more exquisite delight in the progress which I make in the doctrine of godliness, than if I abounded in all manner of riches."

15. In thy precepts. That to which I formerly adverted must not be forgotten -- the prophet's not making a boast of his own acquirements, but setting before others an example for their imitation. We are aware that the majority of mankind are so much involved in the cares of the world, as to leave no time or leisure for meditating upon the doctrine of God. To meet this callous indifference, he very seasonably commends diligence and attention. And even were we not so ensnared by the world, we know how readily we lose sight of the law of God, in the daily temptations which suddenly overtake us. It is not therefore without reason that the prophet exhorts us to constant exercise, and enjoins us to direct all our energies to the subject of meditation on God's precepts. And as the life of men is unstable, being continually distracted by the carnality of their minds, he declares that he will consider attentively the ways of God. Subsequently, he repeats the exquisite pleasure he took in this pursuit. For our proficiency in the law of God will be small, until we cheerfully and heartily set our minds upon it. And, in fact, the commencement of a good life consists in God's law attracting us to him by its sweetness. By the same means the lusts of the flesh, too, are subdued or mitigated. In our natural state, what is more agreeable to us than that which is sinful? This will be the constant tendency of our minds, unless the delight which we feel in the law carry us in the opposite direction.