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.
10 Then the servant took ten of his master’s camels and departed, for all his master’s goods were in his hand. And he arose and went to Mesopotamia, to the city of Nahor.
11 And he made his camels kneel down outside the city by a well of water at evening time, the time when women go out to draw water.
12 Then he said, “O Lord God of my master Abraham, please give me success this day, and show kindness to my master Abraham.
13 Behold, here I stand by the well of water, and the daughters of the men of the city are coming out to draw water.
14 Now let it be that the young woman to whom I say, ‘Please let down your pitcher that I may drink,’ and she says, ‘Drink, and I will also give your camels a drink’—let her be the one You have appointed for Your servant Isaac. And by this I will know that You have shown kindness to my master.”
Isaac himself was forty years old by this time (Genesis 25:20), which means Abraham was 140. … Abraham knew there must be such a girl [one who loved God, a virgin, one who loved her own family, but would be OK with making her home in Canaan] somewhere, because he trusted God to provide the promised seen through Isaac; and for this Isaac must have the right woman for a wife. He had recently learned of his brother Nahor, and had even learned that Nahor had a young granddaughter named Rebekah (Genesis 22:20, 23). — Morris, page 392-393.
Abraham was adamant in insisting that Isaac not go, probably because he had learned by then that the heir of God’s promises should stay in the promised land. As a matter of fact, during all his life, Isaac never left Canaan at all (Genesis 26:2-3). If Issac had gone in search of a bride, there might have been too great a temptation for him to stay with her among her own people, rather than to return to Canaan.
Therefore, Abraham sent his servant on the mission. This man was the steward of all his house, the oldest and most trusted one of his servants. If Eliezer was still living (Genesis 15:2), then he doubtless was the man. However, this event took place over fifty years after Eliezer’s name had been mentioned, so me may well have been dead by this time. — Morris, page 393.
The sign and seal of the oath was a strange one. The servant was to “put his hand under the thigh of Abraham,” while making the promise. The only other occasion on which a similar procedure was used was the time Jacob asked Joseph to put his hand under his thigh and promise he would not bury him in Egypt (Genesis 47:29). the exact meaning of this phrase is obscure. The word “thigh” is frequently also translated “side” or “shaft.” On two important occasions, it refers to the loins. For example, In Genesis 46:26, it obviously refers to the procreative system: “All the souls that came with Jacob into Egypt, which came out of his loins …”
All the ancient Jewish commentators understood this promise to be a euphemism for placing the hand under the male genital organ, and to have a symbolic meaning akin to that of circumcision, so far as the patriarchs were concerned. It was a most solemn oath, in any event, and clearly was related to God’s promise in connection with both the promised land and the promised seed. — Morris, page 394.
The servant immediately set out to equip a caravan for the journey and for the accomplishment of his mission. This required taking provisions for the long trip, a large quantity of his master’s goods (or “valuables”) as presents for the prospective bride and her family, and enough attendants (Genesis 24:59) for protection and other needs of the journey. … Abraham’s servant knew that the women of the place would come out to the wells to draw water for their households in the early evening, and this seemed the best place to meet them.
Drawing enough water to satisfy the thirst of ten large and tired camels would be a hard and wearisome task, to say the least. He couldn’t really ask a girl to do such a thing. Nevertheless, if she would do it voluntarily, it would be a strong indication that she was the right one. Accordingly, he decided to pray to this specific end. — Morris, page 396.
To appreciate the truly outstanding character (viz., kindness and graciousness) that this would indicate, one should bear in mind that the servant had with him ten camels, and the typical one-humped camel found throughout the Middle East can take 26-40 gallons in one drink! — Wechsler, page 218.