Psalms 40:4

4. Blessed is the man who hath set Jehovah for his confidence David here relates what ground for good hope his deliverance would give to all the faithful; inasmuch as, setting aside all the allurements of the world, they would thereby be encouraged to commit themselves with confidence to the protection of God; persuaded not only that they are happy who trust in him alone, but that all other expectations at variance with this are deceitful and cursed. This assurance is not natural to us, but is derived partly from the word of God, and partly from his works; although, as I have said before, the contemplation alone of the works of God would not kindle this light within us, unless God, illuminating us by his word, should show us his benevolence. After having promised to be gracious to us, in manifesting also his goodness by indubitable proofs, he confirms with his own hand what he had previously uttered with his lips. David, therefore, from the fact of his having been restored to life from the abyss of death, justly declares that the faithful are taught from this proof — what men are naturally so reluctant to believe — that they are happy who trust in God alone.

As the instability of our nature commonly tends to draw us downward, and as all of us, from our proneness to yield to delusions, are tempted by many wicked examples, David immediately adds, that he is blessed who regardeth not the proud Some, indeed, render רהבים, rehabim, the rich, or the great of this world, but improperly, in my opinion; because pride, and turning aside to lies, are two things which David here joins together. To regard the great of the earth, therefore, does not signify, as they suppose, to rely upon their power and riches, as if a man’s welfare depended thereupon, but it rather means to be carried away by their examples, to imitate their conduct. When we are everywhere constantly seeing men puffed up with pride, who despise God, and place their highest felicity in ambition, in fraud, in extortion, in guile, a perverse desire of imitating them steals upon us by degrees; and, especially when every thing turns out according to their wishes, a vain and delusive expectation solicits us to try the same course. David, therefore, wisely, and not without good reason, warns us, that in order to have our mind constantly fixed in simple reliance upon God alone, we must guard against those evil examples which ever seek to allure us on all sides to apostatise from him. Moreover, when he says that the proud turn aside to lying, or vanity, in this way he describes briefly the foolish confidence of the flesh. What else is the pride of those who put their own fancies in the place of God but a vain illusion? Certainly the man who, puffed up by the breath of fond conceit, arrogates any thing in the least degree to himself, flatters himself to his own destruction. In short, pride and vanity are opposed to the holy confidence which relies upon God alone; for there is nothing more difficult to the flesh than to trust in God alone, and the world is always full of proud and haughty men, who, soothing themselves with vain allurements, would soon corrupt the minds of the godly, if this arrest were not laid upon them, to restrain, as with a bridle, their erroneous and extravagant opinions.