Genesis 12:7

And the LORD appeared unto Abram, and said, Unto thy seed will I give this land: and there builded he an altar unto the LORD, who appeared unto him.

Unto thy seed ... give this land. From that time Canaan became "The Land of Promise." God was dealing with Abram not in his private and personal capacity merely, but with a view to high and important interests in future ages. That land his posterity was for centuries to inhabit as a special people; the seeds of divine knowledge were to be sown there for the benefit of all mankind; and, considered in its geographical situation, it was chosen in divine wisdom the fittest of all lands to serve as the cradle of a divine revelation designed for the whole world.

In other words, God was there to carry out to completion the special dispensation which had been inaugurated with Abram. While in Chaldea, as soon afterward in Egypt also, the people, through the influence of their wise men, had gone into various forms of nature worship, which would ere long lead to the grossest superstition and idolatry, some special means had become indispensably necessary for retaining in the world the revelation of the divine will, and preserving the seeds of a kingdom which should rise and magnify itself over all the kingdoms of the earth. God therefore determined, by a divine interposition, to rescue mankind from moral degradation and ruin: and with that view He chose Abram, by an act of grace, to train him and his posterity in the principles of true religion, assigned them the land of Canaan as their special inheritance, and acted as their king, who, by a system of ceremonial institutions adapted to the receptive capacities of a rude and wayward people, and by a succession of inspired teachers sent by himself, reared them as a nation in the knowledge and worship of the true God, until, in the maturity of their national existence, he promulgated the Gospel, which through their agency was rapidly diffused through the world.

Thus, the training of Abram, which on the part of God was direct, constant, and progressive, had a most important bearing on the religious education of the world; and the dispensation begun with him, though apparently partial and exclusive, was designed from the first to be subservient to the universal good of mankind. 'From this time began that series of the divine oracles which, being first preserved in Abram's family, and afterward secured in record, has never been broken nor lost, but, having successively embraced the Law, the Prophets, and the Gospel, is now completed, to remain the lasting and imperishable monument of revealed truth in the world' (Davidson 'On Prophecy').