Yitzchak was 40 and the time to find him a wife had come. The Eternal didn't want him to marry a woman from the daughters of Kenaan, nor a woman from Egypt. Avraham made his most trustworthy servant, Eliezer, swear by the sign of the circumcision covenant, and sent him to find a wife for his son in the land where his relatives, the descendants of Shem, son of Noach, lived. When Eliezer asked him if he could take Yitzchak there, in case the woman didn't want to come, Avraham said a firm "no", and he did so twice. Why couldn't Yitzchak go to the place from where Avraham had come?

On the one hand we can see that Yitzchak couldn't leave the promised land. Further on, when he tries to go down to Egypt, the Eternal forbids him to do it and orders him to stay in the land (26:2). Yitzchak was the only one of the three patriarchs who wasn't allowed to go to a foreign land. His life was attached to the land of the promise and he had to remain there until the resurrection.

On the other hand, we have to ask ourselves, why didn't Avraham want his son to go visit his cousins and other relatives? What was wrong with that?

The Scriptures reveal that the family Avraham had left was an idolatrous family (Jos. 24:15). Avraham made the decision to leave all kinds of idolatrous practices and live solely for the Creator of heaven and earth (24:3). He knew too well the influence family members can have, and it is very possible that he didn't want to expose his son, Yitzchak to the pressure that comes with family bonds. Yitzchak would be in danger of adopting their pagan customs which would corrupt his soul and damage the redemption plan for the world. Yitzchak was the son of the promise and he had to be protected from any kind of evil corruption.