In the Western Church similar figures usually represent only God the Father. Thomas Aquinas, for example, identifies the Ancient of Days with God the Father, quoting Hilary of Poitiers' comment that "eternity is in the Father".
The Book of Daniel also contains a reference to "someone like a son of man", who is brought up close before the Ancient of Days, and to whom are given "rulership and dignity and kingdom, that the peoples, national groups and languages should all serve even him" (Dan 7:13-14). Some Christian commentators have understood this to describe God the Father bestowing rulership over an everlasting kingdom upon Jesus (who is often called "the Son of man"), which would suggest that the Ancient of Days is not identical with Jesus. It has been noted that "Daniel's vision of the two figures is the only one in which the two divine persons are seen face to face".
–Wikipedia