John Gill Commentary Genesis 24:51

"Behold, Rebekah is before thee, take her, and go, and let her be thy master`s son`s wife, as Jehovah hath spoken." — Genesis 24:51 (ASV)

Behold, Rebekah [is] before you
Not only was present, but she was delivered to him, or his request was granted: take [her], and go, and let her be your master's son's wife ;
not that they meant he should go away directly with her; for they afterwards solicit her stay with them some time; but they agreed that he should bare her and conduct her to Isaac, to be taken by him for his wife: as the Lord has spoken ;
for so they understood the token given to the servant to know her by, as the determination of God.