Genesis 15:5 says, "And he brought him forth abroad, and said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be." The word "seed" refers to his descendant. It is singular, not plural, in number. This is very strange because humanly speaking, if his descendants were to be as numerous as the stars in heaven, "seed" should have been plural. But when God was telling Abraham of the multiplicity of his descendants, He used the word "seed" in the singular. Why does He use the singular form of the word? Who was the one seed? In Galatians 3:16, Paul said, "He does not say, ‘And to the seeds,’ as concerning many, but as concerning one: ‘And to your seed,’ who is Christ." Hence, the seed that God referred to was not many people, but one person. This person was not Isaac, but Christ.
This shows us that the One who inherits the land is the one seed. As far as Abraham was concerned, the seed was Isaac. But in a wider context, the seed is Christ. Isaac was just a shadow; the substance is Christ. In other words, Christ will inherit the land and bless the earth. Both power and authority are with Christ. God’s work of recovery is carried out by Christ, not by Isaac.
The matter of sonship is very important. If this matter of sonship and the seed is not settled, no one can carry out God’s recovery work. If Abraham was not brought to the point of perfection, he could not have brought in Isaac. Abraham first had to become a vessel before Isaac could be brought in. This means that the glorious Christ will be brought in only when a group of people believe as Abraham believed; only then will God’s work be accomplished. Isaac was merely a shadow; the reality is Christ. In the same way, Abraham was a shadow; the reality is the church. Just as Abraham became a vessel to bring in Isaac, so the church is a vessel to bring in the glorious Christ.
God wanted Abraham to become a vessel to bring in Isaac. The descendants of Abraham will fulfill God’s purpose; Abraham himself did not fulfill God’s purpose. Hence, the church is nothing in itself. What is important is that the church brings in Christ and expresses Christ on earth for the recovery of all God’s work on earth. Abraham was a vessel to bring in Isaac. Today the church is a vessel to bring in Christ.
(The God of Abraham, Isaac, and Jacob, Chapter 4, by Watchman Nee)