Genesis 12:3

and I will bless them that bless thee, and curse him that curseth thee; and in thee shall all families of the earth be blessed. Here are promises of both temporal and spiritual blessings. To the first belongs the fact that Abram's descendants were to be so great in number as to be a great nation. But of far greater importance are the promises that refer to spiritual gifts. For that Abram's name should be great, that the blessing of the Lord should rest upon him, that he should be distinguished so highly among men as to receive the thankful praises and the blessings of men and be shielded against any curse, that in him should be blessed all the families and tribes of the earth, all mankind: all this does not refer to any mere outward wealth which the Lord intended to shower upon Abram. The blessing rather, as the repetitions and extensions show, Genesis 18:18; Genesis 22:18; Genesis 26:4, indicated that Abram (or Abraham) was to be a source of everlasting spiritual gifts and blessings through his seed, through one descendant in the great and blessed nation which would call him father, namely, through the Messiah, Jesus Christ, Acts 3:25; Galatians 3:16. The prophecy of the Seed of the woman, which had been narrowed down in a general way in the blessing upon Shem, was here given expressly to Abram and to the nation which was to descend from him.