John Calvin Commentary Genesis 24:6

"And Abraham said unto him, Beware thou that thou bring not my son thither again." — Genesis 24:6 (ASV)

Beware that thou bring not my son thither again. If the woman should not be found willing, Abraham, entrusting the outcome to God, firmly adheres to the main point: that his son Isaac should not return to his country, because in this way he would have forfeited the promised inheritance. He therefore chooses instead to live by hope, as a stranger, in the land of Canaan, rather than to rest among his relatives in his native land.

And so we see that, in difficult and confusing situations, the mind of the holy man was not distracted from the command of God by any troubling worries; and we are taught, by his example, to follow God through every obstacle. However, he later declares that he expects better things. By such words he strengthens the confidence of his servant, so that the servant, anticipating a successful outcome with greater eagerness, might prepare for the journey.