Three things we may observe here concerning Abraham: -
I. The care he took of a good son, to get him married, well married. It was high time to think of it now, for Isaac was about forty years old, and it had been customary with his ancestors to marry at thirty, or sooner, Gen 11:14, Gen 11:18, Gen 11:22, Gen 11:24. Abraham believed the promise of the building up of his family, and therefore did not make haste; not more haste than good speed. Two considerations moved him to think of it now (Gen 24:1): - 1. That he himself was likely to leave the world quickly, for he was old, and well-stricken in age, and it would be a satisfaction to him to see his son settled before he died; and, 2. That he had a good estate to leave behind him, for the Lord had blessed him in all things; and the blessing of the Lord makes rich. See how much religion and piety befriend outward prosperity. Now Abraham's pious care concerning his son was, (1.) That he should not marry a daughter of Canaan, but one of his kindred. He saw that the Canaanites were degenerating into great wickedness, and knew by revelation that they were designed for ruin, and therefore he would not marry his son among them, lest they should be either a snare to his soul, or at least a blot to his name. (2.) That yet he should not leave the land of Canaan, to go himself among his kindred, not even for the purpose of choosing a wife, lest he should be tempted to settle there. This caution is given Gen 24:6, and repeated, Gen 24:8. "Bring not my son thither again, whatever comes of it. Let him rather want a wife than expose himself to that temptation." Note, Parents in disposing of their children, should carefully consult the welfare of their souls, and their furtherance in the way to heaven. Those who through grace have escaped the corruption that is in the world through lust, and have brought up their children accordingly, should take heed of doing any thing by which they may be again entangled therein and overcome, Pe2 2:20. Beware that you bring them not thither again, Heb 11:15.
II. The charge he gave to a good servant, probably Eliezer of Damascus, one of whose conduct, fidelity, and affection to him and his family, he had had long experience. He trusted him with this great affair, and not Isaac himself, because he would not have Isaac go at all into that country, but marry there by proxy; and no proxy so fit as this steward of his house. This matter is settled between the master and the servant with a great deal of care and solemnity. 1. The servant must be bound by an oath to do his utmost to get a wife for Isaac from among his relations, Gen 24:2-4. Abraham swears him to it, both for his own satisfaction and for the engagement of his servant to all possible care and diligence in this matter. Thus God swears his servants to their work, that, having sworn, they may perform it. Honour is here done to the eternal God; for he it is that is sworn by, to whom alone these appeals ought to be made. And some think honour is done to the covenant of circumcision by the ceremony here used of putting his hand under his thigh. Note, Swearing being an ordinance not peculiar to the church, but common to mankind, is to be performed by such signs as are the appointments and common usages of our country, for binding the person sworn. 2. He must be clear of this oath if, when he had done his utmost, he could not prevail. This proviso the servant prudently inserted (Gen 24:5), putting the case that the woman would not follow him; and Abraham allowed the exception, Gen 24:8. Note, Oaths are to be taken with great caution, and the matter sworn to should be rightly understood and limited, because it is a snare to devour that which is holy, and, after vows, to make the enquiry which should have been made before.
III. The confidence he put in a good God, who, he doubts not, will give his servant success in this undertaking, Gen 24:7. He remembers that God had wonderfully brought him out of the land of his nativity, by the effectual call of his grace; and therefore doubts not but he will succeed him in his care not to bring his son thither again. He remembers also the promise God had made and confirmed to him that he would give Canaan to his seed, and thence infers that God would own him in his endeavours to match his son, not among those devoted nations, but to one that was fit to be the mother of such a seed. "Fear not therefore; he shall send his angel before thee to make thy way prosperous." Note, 1. Those that carefully keep in the way of duty, and govern themselves by the principles of their religion in their designs and undertakings, have good reason to expect prosperity and success in them. God will cause that to issue in our comfort in which we sincerely aim at his glory. 2. God's promises, and our own experiences, are sufficient to encourage our dependence upon God, and our expectations from him, in all the affairs of this life. 3. God's angels are ministering spirits, sent forth, not only for the protection, but for the guidance, of the heirs of promise, Heb 1:14. "He shall send his angel before thee, and then thou wilt speed well."

Put his hand under the thigh of Abraham - This form of swearing has greatly puzzled the commentators; but it is useless to detail opinions which I neither believe myself, nor would wish my readers to credit. I believe the true sense is given in the Targum of Jonathan ben Uzziel, and that called the Jerusalem Targum. In the former it is said, Put now thy hand בגזית מהולתי bigzirath mehulathi, in sectione circumcisionis meoe; in the latter תחות ירך קימי techoth yerech keyami, sub femore foederis mei. When we put the circumstances mentioned in this and the third verse together, we shall find that they fully express the ancient method of binding by oath in such transactions as had a religious tendency. 1. The rite or ceremony used on the occasion: the person binding himself put his hand under the thigh of the person to whom he was to be bound; i.e., he put his hand on the part that bore the mark of circumcision, the sign of God's covenant, which is tantamount to our kissing the book, or laying the hand upon the New Testament or covenant of our Lord Jesus Christ. 2. The form of the oath itself: the person swore by Jehovah, the God of heaven and the God of the earth. Three essential attributes of God are here mentioned:
1. His self-existence and eternity in the name Jehovah.
2. His dominion of glory and blessedness in the kingdom of heaven.
3. His providence and bounty in the earth.
The meaning of the oath seems to be this: "As God is unchangeable in his nature and purposes, so shall I be in this engagement, under the penalty of forfeiting all expectation of temporal prosperity, the benefits of the mystical covenant, and future glory." An oath of this kind, taken at such a time, and on such an occasion, can never be deemed irreligious or profane. Thou shalt swear by his name - shalt acknowledge and bind thyself unto the true God, as the just Judge of thy motives and actions, is a command of the Most High; and such an oath as the above is at once (on such an occasion) both proper and rational. The person binding himself proposes for a pattern the unchangeable and just God; and as He is the avenger of wrong and the punisher of falsehood, and has all power in the heavens and in the earth, so he can punish perjury by privation of spiritual and temporal blessings, by the loss of life, and by inflicting the perdition due to ungodly men, among whom liars and perjured persons occupy the most distinguished rank. Our ideas of delicacy may revolt from the rite used on this occasion; but, when the nature of the covenant is considered, of which circumcision was the sign, we shall at once perceive that this rite could not be used without producing sentiments of reverence and godly fear, as the contracting party must know that the God of this covenant was a consuming fire.

And the servant put his hand under the thigh of Abraham his master,.... Or "then" or "therefore the servant", &c. (n) being satisfied of the nature and extent of his oath, and thoroughly understanding how he was to act upon it, readily took it by using this rite; see Gill on Gen 24:2,

and sware to him concerning that matter; of taking a wife to his son, engaging to do everything he had directed and enjoined him relative to it.

(n) "posuit ergo", V. L. "igitur", Tigurine version; "itaque", Junius & Tremellius, Piscator; "ita", Drusius; "tum", Schmidt.

thou shalt not take a wife, &c.--Among pastoral tribes the matrimonial arrangements are made by the parents, and a youth must marry, not among strangers, but in his own tribe--custom giving him a claim, which is seldom or never resisted, to the hand of his first cousin. But Abraham had a far higher motive--a fear lest, if his son married into a Canaanitish family, he might be gradually led away from the true God.