"And the angel of the Lord called out of heaven and said. . . . and the angel of the Lord called unto Abraham out of heaven the second time and said, By myself I have sworn, saith the Lord [Jehovah]. . . ."

                                       Again the angel of the Lord is compared with the Lord [Jehovah].

                It was either the Father or the Son , NOT the Holy Spirit that appeared to Abraham because it was a tangible appearance.