Genesis 24

Ge 24:1 Now Abraham was old, well advanced in age; and the LORD had blessed Abraham in all things.

2 So Abraham said to the oldest servant of his house, who ruled over all that he had, "Please, put your hand under my thigh,

3 "and I will make you swear by the LORD, the God of heaven and the God of the earth, that you will not take a wife for my son from the daughters of the Canaanites, among whom I dwell;

4 "but you shall go to my country and to my family, and take a wife for my son Isaac."

5 And the servant said to him, "Perhaps the woman will not be willing to follow me to this land. Must I take your son back to the land from which you came?"

6 But Abraham said to him, "Beware that you do not take my son back there.

7 "The LORD God of heaven, who took me from my father's house and from the land of my family, and who spoke to me and swore to me, saying, 'To your descendants I give this land,' He will send His angel before you, and you shall take a wife for my son from there.

8 "And if the woman is not willing to follow you, then you will be released from this oath; only do not take my son back there."

9 So the servant put his hand under the thigh of Abraham his master, and swore to him concerning this matter.

Abraham, in an act of faith, to God's promise instructed his servant that Isaac should not be taken back to where God took him and that his bride should not be from the Canaanites.

He had his eyes on God's Word that God would give the land to him and his descendants and that He would cause them to become as many as the stars. This would require refraining from mixing with the Canaanites in marriage.

Moses is showing his original Israelite readers not to mix in marriage with the nations around them.

The remaining verses from verse 10 to verse 61, we find Moses encouraging the men in Israel not to marry anyone from the Canaanites. Moses here shows them the fact that God knows how to find a wife for the men in Israel. That God's blessing will be on a marriage which is in line with His will.  

Pr 19:14 Houses and riches are an inheritance from fathers, But a prudent wife is from the LORD.