4. Enter his gates. The conclusion of the psalm is almost the same as the beginning of it, excepting that he adopts a mode of speech which relates to the worship of God which obtained under the law; fd126 in which, however, he merely reminds us that believers, in rendering thanks to God, do not discharge their duty aright, unless they also continue in the practice of a steady profession of piety. Meanwhile, under the name of the temple, he signifies that God cannot be otherwise worshipped than in strict accordance with the manner prescribed in his law. And, besides, he adds, that God’s mercy endureth for ever, and that his truth also is everlasting, to point out to us that we can never be at a loss for constant cause of praising him. If, then, God never ceases to deal with us in this manner, it would argue the basest ingratitude on our part, if we wearied in rendering to Him the tribute of praise to which he is entitled. We have elsewhere taken notice of the reason why truth is connected with mercy. For so foolish are we, that we scarcely feel the mercy of God while he openly manifests it, not even in the most palpable displays of it, until he open his holy lips to declare his paternal regard for us.
David was not as yet put in possession of the kingdom, but having been already created king by the appointment of God, he prepares himself for exercising the government in the best manner. And he not only stirs up himself to perform faithfully the duties of his kingly office by devoutly meditating on this subject, but also engages by a solemn vow to be God’s faithful servant, in order to induce Him to put him speedily in possession of the kingdom.