Genesis 24:2

“And Abraham said unto his eldest servant of his house, etc.] To Eliezer his servant, according to the Targum of Jonathan, and as is generally thought; and who may well be called an old servant, and his oldest servant, since he must have lived with him fifty years and upwards; one may trace him near sixty years in Abraham’s family, and it is highly probable he lived much longer; he was his servant when he had the vision between the pieces, (<011502>Genesis 15:2); and then he was the steward of his house, and bid fair to be his heir; which was some time before Hagar was given to Abraham; and Ishmael his son by Hagar was fourteen years of age when Isaac was born, and he was now forty years old,…”

“said unto his eldest servant--Abraham being too old, and as the heir of the promise not being at liberty to make even a temporary visit to his native land, was obliged to intrust this delicate mission to Eliezer, whom, although putting entire confidence in him, he on this occasion bound by a solemn oath. A pastoral chief in the present day would follow the same course if he could not go himself.”

“24:2 Putting his hand under Abraham’s thigh (cp. 47:29), the servant took a very solemn oath, assuming the burden of completing this mission.”