Genesis 12:2

2. And I will make of thee a great nation. Hitherto Moses has related what Abram had been commanded to do; now he annexes the promise of God to the command; and that for no light cause. For as we are slothful to obey, the Lord would command in vain, unless we are animated by a superadded confidence in his grace and benediction. Although I have before alluded to this, in the history of Noah, it will not be useless to inculcate it again, for the passage itself requires something to be said; and the repetition of a doctrine of such great moment ought not to seem superfluous. For it is certain that faith cannot stand, unless it be founded on the promises of God. But faith alone produces obedience. Therefore in order that our minds may be disposed to follow God, it is not sufficient for him simply to command what he pleases, unless he also promises his blessing. We must mark the promise, that Abram, whose wife was still barren, should become a great nation. This promise might have been very efficacious, if God, by the actual state of things, had afforded ground of hope respecting its fulfillment; but now, seeing that the barrenness of his wife threatened him with perpetual privation of offspring, the bare promise itself would have been cold, if Abram had not wholly depended upon the word of God; wherefore, though he perceives the sterility of his wife, he yet apprehends, by hope, that great nation which is promised by the word of God. And Isaiah greatly extols this act of favor, that God, by his blessing, increased his servant Abram whom he found alone and solitary to so great a nations (Isaiah 2:2.) The noun גוי(goi,) “my nation,” (Genesis 12:4,) though detestable to the Jews, is in this place, and in many others, taken as a term of honor. And it is here used emphatically, to show that he should not only have posterity from his own seed in great number, but a peculiar people, separated from others, who should be called by his own name.

I will bless thee. This is partly added, to explain the preceding sentence. For, lest Abram should despair, God offers his own blessing, which was able to effect more in the way of miracle, than is seen to be effected, in other cases, by natural means. The benediction, however, here pronounced, extends farther than to offspring; and implies, that he should have a prosperous and joyous issue of all his affairs; as appears from the succeeding context, “And will make thy name great, and thou shalt be a blessing.” For such happiness is promised him, as shall fill all men everywhere with admiration, so that they shall introduce the name of Abram, as an example, into their formularies of pronouncing benediction. Others use the term in the sense of augmentation, ‘Thou shalt be a blessing,’ that is, ‘All shall bless thee.’ But the former sense is the more suitable. Some also expound it actively, as if it had been said, ‘My grace shall not reside in thee, so that thou alone mayest enjoy it, but it shall flow far unto all nations. I therefore now so deposit it with thee, that it may overflow into all the world.’ But God does not yet proceed to that communication, as I shall show presently.