Genesis 24:7

The LORD God of heaven, which took me from my father's house, and from the land of my kindred, and which spake unto me, and that sware unto me, saying, Unto thy seed will I give this land; he shall send his angel before thee, and thou shalt take a wife unto my son from thence.

The Lord God of heaven ... shall send his angel before thee. This was said in answer to the natural enquiries of the servant what course he should follow in the eventuality of certain specified contingencies. Abraham had received no revelation respecting this mission; but he justly concluded, from his past experience, that the covenant God whom he had faithfully served, and who had given him so many tokens of His approval and blessing, would pave the way for the successful accomplishment of this embassy, which was planned for the furthering of the interests of His kingdom. He had seen angels as well as heard their voice; but he knew that, also unseen and unheard, they were employed in ministering to the servants of God (cf. Hebrews 1:14); and the sequel fully justified the confidence he expressed.