30. Their seed shall serve him, and shall be registered to the Lord for a generation.31. They shall come, and shall declare his righteousness to a people that shall be born, because he hath done it.
30. Their seed shall serve him. The more to exalt the greatness of the benefit, he declares that it will be of such a character that posterity will never forget it. And he shows how it will come to be perpetuated, namely, because the conversion of the world, of which he has spoken, will not be for a short time only but will continue from age to age. Whence we again conclude, that what is here celebrated is not such a manifestation of the glory of God to the Gentile nations as proceeds from a transitory and fading rumor, but such as will enlighten the world with its beams, even to the end of time. Accordingly, the perpetuity of the Church is here abundantly proved, and in very clear terms: not that it always flourishes or continues in the same uniform course through successive ages, but because God, unwilling that his name should be extinguished in the world, will always raise up some sincerely to devote themselves to his service. We ought to remember that this seed, in which the service of God was to be preserved, is the fruit of the incorruptible seed; for God begets and multiplies his Church only by means of his word.
The expression, To be registered to the Lord for a generation, is explained in two ways. Some take the Hebrew word dvr, dor, for a succession of ages, and explain the clause thus: They shall be registered to the Lord age after age. Others take it for generation, in the sense in which the word natio [nation] is used in the Latin tongue. As both these senses suit very well, and come almost to the same thing, I leave my readers at liberty to choose between them. I am, however, I admit, rather inclined to the opinion, that by this word is designated God's chosen people and peculiar nation, which may be accounted the heritage of God. Farther, as the name Jehovah, which is expressive of God's essence, is not here used as it is a little before, but the word Adonai, I do not disapprove of the opinion of those who think that Christ is here expressly invested with authority over the Church, that he may register all who shall give in their names as on the side of God his Father. And, indeed, as our heavenly Father has committed all his chosen ones to the protection and guardianship of his own Son, he acknowledges as his people none but those who belong to the flock of Christ.
31. They shall come, and shall declare. The Psalmist here confirms what I have previously stated, that since the fathers will transmit the knowledge of this benefit to their children, as it were from hand to hand, the name of God will be always renowned. From this we may also deduce the additional truth, that it is by the preaching of the grace of God alone that the Church is kept from perishing. At the same time, let it be observed, that care and diligence in propagating divine truth are here enjoined upon us, that it may continue after we are removed from this world. As the Holy Spirit prescribes it as a duty incumbent on all the faithful to be diligent in instructing their children, that there may be always one generation after another to serve God, the sluggishness of those who have no scruple of conscience in burying the remembrance of God in eternal silence, a sin with which those are virtually chargeable who neglect to speak of him to their children, and who thus do nothing to prevent his name from utterly perishing, is condemned as involving the greatest turpitude. The term righteousness, in this place, refers to the faithfulness which God observes in preserving his people, of which we have a memorable example in the deliverance of David. In defending his servant from the violence and outrage of the wicked, he proved himself to be righteous. Hence we may learn how dear our welfare is to God, seeing he combines it with the celebration of the praise of his own righteousness. If then the righteousness of God is illustriously manifested in this, that he does not disappoint us of our hope, nor abandon us in dangers, but defends and keeps us in perfect safety, there is no more reason to fear that he will forsake us in the time of our need, than there is reason to fear that he can forget himself. We must, however, remember that it is not for any particular succor afforded to one individual, but it is for the redemption of the human race, that the celebration of the praise of God is required from us in this passage. In short, the Holy Spirit, by the mouth of David, recommends to us the publication of Christ's resurrection. In the end of this psalm some commentators resolve the particle ky, ki, because, into the pronoun 'sr, asher, which, as if it had been said, The righteousness which he hath done. But the sentence will be fuller if we read, because, and explain the passage thus: They shall come, and shall declare his righteousness, because God shall have given proof, or demonstration, of his righteousness - shall have afforded evidence by the effect, or the deed itself, that he is the faithful guardian of his own people.