It was after his father's death that a second and more definite call came to Abram with a magnificent promise attached to it. And this was the Divine intimation: "Get thee out of thy country, and from thy kindred, and from thy father's house, unto the land that I will show thee; and I will make of thee a great nation, and I will bless thee, and make thy name great; and be thou a blessing; and I will bless them that bless thee, and him that curseth thee will I curse: and in thee shall all the families of the earth be blessed." Here was a threefold blessing promised—partly temporal, partly spiritual. He was to be brought unto a land where he should make his home; he was to become a great nation; and in and through him all the families of the earth should be blessed. ... He now saw in the Lord, not merely the great Creator, but also a moral Governor; he recognized His ruling Providence; he knew that it was God's will that he should settle in the land to which he was directed, that in this new home he and his posterity should receive some extraordinary blessings, and that from his seed should spring some wonderful good to all mankind. This solemn promise filled his soul, directed all his conduct, made him cling with such affection to the land of Canaan with which the blessing was inseparably connected. He was now of mature age. ... Fifteen years had passed since the Lord had appeared to him in Ur, and he had obediently set out on his pilgrimage. He had had time for mediation on this call, and for fortifying his resolve to follow the guiding hand. In giving himself up to God he had done so unreservedly. Of the old superstitions in which he was brought up not a trace remained. ... He received his new creed wholly and implicitly, and acknowledged the duties which it imposed upon him. A living faith involves action; its result is practice. So Abram recognized the moral obligation arising from a more perfect revelation, and "went out, not knowing whither he went."
—From "Abraham: His Life and Times," by