פּירוש אויף בראשית 24:3

מבנות הכנעני, “from among the daughters of the Canaanite nation.” Avraham did not want that in the future anyone could claim that his claim on the Holy Land was based on intermarriage with the previous owners of that land. It had to be established beyond any shadow of a doubt that the Israelites’ claim to the land was based on G-d having firmly promised it to me.

AND I WILL MAKE THEE SWEAR BY THE ETERNAL. It would have been proper for Abraham to command his son Isaac that he should not take a wife from the daughters of Canaan. But since it was his wish to dispatch someone during his lifetime to his country and his family, and he made the servant swear to do so whether in his lifetime or after his death, therefore Abraham found it necessary in any case to make the servant swear to go there. In addition he found it necessary to say to him, “I command you that you should not take a woman for my son of the daughters of Canaan. Instead you are to go to my country and take for him a wife from my father’s house.” Now having required the servant to swear to this, he no longer found it necessary to command Isaac at all for he knew that he would not transgress his father’s wish or the oath which he made his servant swear, as the matter was indeed known to Isaac.
It is also possible that the servant Eliezer was the administrator of his possessions, and Abraham commanded him to marry off Isaac in accordance with his will and cause him to inherit his estate on this condition, [namely, that he marry in accordance with his father’s wish]. This is the significance of the expression, that ruled over all that he had.⁸⁰Verse 2 here.

1. And the reason for telling us the God of the Heavens and the God of the land is because in this place when a daughter is set up with someone (a shidduch) it is really from Heaven. And this is a secret.