By thy statutes I have acquired understanding The prophet seems here to invert the order he has just now laid down. He observed that he had kept his feet from going astray, that he might observe God's Law, and now he institutes a contrary order, beginning with the observance of the Law; for he declares that he had been taught by the word of God before he amended his faults. Yet these two things are not inconsistent, -- that the faithful should withdraw themselves from their wanderings, in order to frame their life according to the rule of God's word, and that when they are already advanced a considerable way in a holy life, the fear of God being then more vigorous in them, they should regard all vices with more intense hatred. The beginning of a good life, unquestionably, is when a man endeavors to purge himself from vices; and the more a man has made progress in a good life, he will burn with a, proportionate zeal in his detestation of vices and in shunning them. Moreover, we are taught by the words of the prophet, that the reason why men are so involved in falsehoods, and entangled in perverse errors, is, because they have not learned wisdom from the word of God. As the whole world are given to folly, those who wander astray plead in excuse, that it is difficult for them to guard against the allurements of vice. But the remedy will be near at hand, if we follow the counsel of the prophet; that is to say, if, instead of leaning on our own wisdom, we seek understanding from the word of God, in which he not only shows what is right:. but also fortifies our minds, and puts us on our guard against all the deceits of Satan, and all the impostures of the world. Would to God that, at the present day, this were thoroughly impressed on the minds of all who boast themselves of being Christians; for then they would not be continually driven about, as the greater part of them are, with such inconstancy, according to the conflicting impulses of prevailing opinions. As Satan is so sedulously exerting himself to spread abroad the mists of error, let us apply ourselves with the greater earnestness to the acquisition of this wisdom.

Through thy precepts I get understanding - A true understanding; a correct view of things; a knowledge of thee, of myself, of the human character, of the destiny of man, of the way of salvation - the best, and the only essential knowledge for man. This knowledge the psalmist obtained from the "precepts" of God; that is, all that God had communicated by revelation. This passage expresses in few words what had been said more at length in Psalm 119:98-100.
Therefore I hate every false way - I see that which is right and true, and I pursue it. In proportion as I have a just knowledge of truth and duty, I hate that which is false and evil.

Through thy precepts I get understanding - Spiritual knowledge increases while we tread in the path of obedience. Obedience is the grand means of growth and instruction. Obedience trades with the talent of grace, and thus grace becomes multiplied.

Through thy precepts I get understanding,.... Of the will of God; of his worship, the nature and manner of it; of his ordinances, their use and importance; and of his doctrines, and the excellency of them;
therefore I hate every false way; of worship; all superstition and will worship, the commandments and inventions of men, and every false doctrine; all lies in hypocrisy, for no lie is of the truth; every thing that is contrary to the word of God, and is not according to truth and godliness. The Targum is,
"I hate every lying man.''