Direct my steps according to thy word. By these words he shows, as he has often done before in other places, that the only rule of living well is for men to regulate themselves wholly by the law of God. We have already repeatedly seen in this Psalm, that so long as men allow there-selves to wander after their own inventions, God rejects whatever they do, however laborious the efforts they may put forth. But as the Prophet declares that men's lives are then only framed aright when they yield themselves wholly to the obeying of God, so, on the other hand, he confesses that to do this is not within their own will or power. God's law, it is evident, will not make us better by merely prescribing to us what is right. Hence the outward preaching of it is compared to a dead letter. David, then, well instructed in the law, prays for an obedient heart being given him, that he may walk in the way set before him. Here two points are particularly deserving of our notice -- first, that God deals bountifully with men, when he invites them to himself by his word and doctrine; and, secondly, that still all this is lifeless and unprofitable, until he govern by his Spirit those whom he has already taught by his word. As the Psalmist desires not simply to have his steps directed, but to have them directed to God's word, we may learn that he did not hunt after secret revelations, and set the word at nought, as many fanatics do, but connected the external doctrine with the inward grace of the Holy Spirit; and herein consists the completeness of the faithful, in that God engraves on their hearts what he shows by his word to be right. Nothing, therefore, is more foolish than the fancy of those who say, that in enjoining upon men what he would have them to do, God estimates the strength which they have to perform it. In vain does divine truth sound in our ears, if the Spirit of God does not effectually pierce into our hearts. The Prophet confesses that it is to no purpose for him to read or hear the law of God, unless his life is regulated by the secret influence of the Holy Spirit, that he may thus be enabled to walk in that righteousness which the law enjoins. In the second clause he reminds us how necessary it is for us to be continually presenting this prayer at the throne of grace, acknowledging that he is the bond-slave of sin until God stretch forth his hand to deliver him. direct me, says he, that iniquity may not have dominion in me. [1] So long, then, as we are left to ourselves, Satan exercises', over us his despotic sway uncontrolled, so that we have not power to rid ourselves of iniquity. The freedom of the godly consists solely in this -- that they are governed by the Spirit of God, and thus preserved from succumbing to iniquity, although harassed with hard and painful conflicts.

Footnotes

1 - vy, bi, IN me. Let me have no governor but God; let the throne of my heart be filled by him, and none other. -- Dr. Adam Clark

Order my steps in thy word - My goings, or, my conduct and life - by thy word; according to thy requirements. Let me be wholly obedient to thy will.
And let not any iniquity have dominion over me - See the notes at Psalm 19:13. The prayer is, that no form of sin, that no wicked passion or propensity, might be allowed to rule over him. He who is willing that any one sin should rule in his heart, though he should be free from all other forms of sin, cannot be a pious man. See the notes at James 2:10.

Order my steps - הכן hachen, make them firm; let me not walk with a halting or unsteady step.
Have dominion over me - בי bi, In me. Let me have no governor but God, let the throne of my heart be filled by him, and none other.

Order my steps in thy word,.... Or, "by thy word" (s), or "according" to it. Which is the rule of practice and action, as well as of faith; and happy are they who walk according to the directions of it; but it is not in the power of man to order and direct his steps: this is done by the Lord; and such who acknowledge him in their ways, and apply to him for direction, are and shall be thus favoured by him; see Jeremiah 10:23;
and let not any iniquity have dominion over me; not only greater sins or presumptuous ones, very gross iniquities, as in Psalm 19:13; but lesser ones, even the least of them. It is a sad thing to be enslaved to any lust or sin, be it what it will: sin reigns over wicked men even unto death; and it oftentimes has great power over good men, puts them upon doing that which is evil, and hinders them from doing that which is good; it carries them captive, and threatens to have the ascendant over them, and rule in them, which they deprecate; and such a prayer may be the prayer of faith, since it is promised "sin shall not have the dominion over you", Romans 6:14. Kimchi interprets this of the evil imagination or corruption of nature; R. Moses understands it of a wicked man; and so the Syriac version.
(s) "eloquio tuo", Tigurine version; "secundum eloquium tuum", Musculus.

Order my steps--Make firm, so that there be no halting (Psalm 40:2).
any iniquity-- Psalm 119:34 favors HENGSTENBERG, "any iniquitous man," any "oppressor." But the parallel first clause in this (Psalm 119:33) favors English Version (Psalm 19:13). His hope of deliverance from external oppression of man (Psalm 119:34) is founded on his deliverance from the internal "dominion of iniquity," in answer to his prayer (Psalm 119:33).

Steps - My motions and actions.