“But why does Abraham forbid his servant to look for one of the daughters of the Canaanites? My answer is that Abraham, near death, had experienced many things in this land when he lived among the heathen people. It was necessary for him to observe their customs and way of life rather carefully, to associate with them, and to talk and confer with them about various matters, inasmuch as all his wealth and livelihood—almost as in the case of a shepherd—consisted in cattle and fields. From this source he not only fed and supported his domestics but also sold meat, butter, milk, cheese, and similar products. This could not be done without close association with the inhabitants and citizens. Consequently, as a result of that association and intimacy, some, possibly of the foremost families of Ephron or others, were perhaps induced to desire Isaac, such a respectable and handsome young man, as a son-in-law or relative by marriage. And above it has been stated that because of God’s blessing Abraham was wealthy. For this reason alone they surely wanted to be friends with him.
But Abraham had various reasons for refusing this. He was afraid of dangers either for his household or for his church. Perhaps he did not like the character and the conduct of the girls, because they were exceedingly proud if they were distinguished by wealth, beauty, or descent. For it is especially hard to be a son-in-law in the house of a powerful and rich man, and nothing is more unbearable than a rich and domineering woman; for the husband is forced to comply with his wife’s command and authority, or by their blandishments the women at least prevail over and weaken the men who are in the clutches of love” (Luther’s Works, v.4 p.245-246).