Genesis 24

In the days of Noah we learn that -

"...Noah and his sons hearkened unto the Lord, and gave heed, and they were called the sons of God." (Pearl of Great Price | Moses 8:13)

But we also witness that -

"...daughters were born unto them, the sons of men saw that those daughters were fair, and they took them wives, even as they chose.
15 And the Lord said unto Noah: The daughters of thy sons have sold themselves; for behold mine anger is kindled against the sons of men, for they will not hearken to my voice." (Pearl of Great Price | Moses 8:14 - 15)

Abraham understood the difference between sons of God and sons of men. This same concept would apply to the women. It was important to Abraham that Isaac married a "daughter of God" for Abraham must have been greatly disappointed with Ishmael in that he married a daughter of men. This is so important that Abraham said to his servant -

"...thou shalt go unto my country, and to my kindred, and take a wife unto my son Isaac." (Old Testament | Genesis 24:4)

Abraham was confident that those of "my country" were his kindred that had remained faithful in worshipping the Lord. This was true as we learn of the character of Rebekah as she worshipped the Lord. The results was a continuation of a righteous posterity.

Abraham continues to be a great example in so many ways.