Incline my heart In this verse he confesses the human heart to be so far from yielding to the justice of God, that it is more inclined to follow an opposite course. Were we naturally and spontaneously inclined to the righteousness of the law, there would be no occasion for the petition of the Psalmist, Incline my heart It remains, therefore, that our hearts are full of sinful thoughts, and wholly rebellious, until God by his grace change them. This confession on the part of the prophet must not be overlooked, That the natural corruption of man is so great, that he seeks for any thing rather than what is right, until he be turned by the power of God to new obedience, and thus begin to be inclined to that which is good. In the second clause of the verse the prophet points to those impediments which prevent mankind from attaining to the desire of righteousness; their being inclined to covetousness. By a figure of speech, [1] in which a part is put for the whole, the species is put for the genus. The Hebrew term, vts batsang, signifies to use violence, or to covet, or to defraud; but covetousness is most in accordance with the spirit of the passage, provided we admit the prophet to have selected this species, "the root of all evils," to demonstrate that nothing is more opposed to the righteousness of God, (1-Timothy 6:10). We are here instructed generally, that we are so much under the influence of perverse and vicious affections, our hearts abhor the study of God's law, until God inspire us with the desire for that which is good.

Footnotes

1 - Per Synecdochen.

Incline my heart unto thy testimonies - Cause my heart to be inclined to them, or to be disposed to keep them. This, too, is a recognition of dependence, and a prayer for guidance.
And not to covetousness - To gain; to the love of money. This seems to be referred to here as the principal thing which would turn away the heart from religion, or as that from which the most danger was to be feared. There are undoubtedly many other things which will do this - for all sin will do it; but this was the chief danger which the psalmist apprehended in his own case, and perhaps he meant to refer to this as the principal danger on this subject which besets the path of man. There are manymore persons turned away from the service of God, and kept away from it, by covetousness than there are by any other one sin. When the psalmist prays that God would not "incline" his heart to covetousness, the language is similar to that in the Lord's prayer - "And lead us not into temptation." That is, Restrain us from it; let us not be put in circumstances where we shall be in danger of it. We are not to suppose that God exerts any positive influence either to make a man covetous, or to tempt him. See James 1:13-14.

Not to covetousness - Let me have no inordinate love for gain of any kind, nor for any thing that may grieve thy Spirit, or induce me to seek my happiness here below.

Incline my heart unto thy testimonies, and not to (c) covetousness.
(c) By this, meaning all other vices, because covetousness is the root of all evil.

Incline my heart unto thy testimonies,.... To read the word of God, to hear it opened and explained, to observe and keep the things contained in it; to which there is a disinclination in men naturally: but the Lord, who fashions the hearts of men, and has them in his hands, can bend and incline them by his efficacious grace to regard these his testimonies; which, as Aben Ezra observes, are more precious than all substance, and so are opposed to what follows:
and not to covetousness; not to mammon or money, as the Targum; the love of it, which is the root of all evil, and very pernicious and harmful; in hearing the word it chokes it, and makes it unfruitful, 1-Timothy 6:9. Not that God inclines the heart to evil, as he does to good; but he may suffer the heart to be inclined, and may leave a man to the natural inclinations of his heart, and to the temptations of Satan, and the snares of the world, which may have great influence upon him; and this is what is here deprecated; see Psalm 141:4.

Covetousness - He mentions this in particular, because it is most opposite to God's testimonies, and does most commonly hinder men from receiving his word, and from profiting by it: and because it is most pernicious, as being the root of all evil.