1. Christ always spake of his coming as that of the Son of Man. By this he himself taught the same truth with which afterward the angel at the ascension reassured the disciples who stood “gazing up into heaven,” namely, that he that shall come then shall be the “same Jesus” which was taken up. It will then be in human form that he will appear, and with the same sympathizing human as well as divine love towards his own which he so wonderfully displayed while on earth.
2. But the apostle Peter, at Pentecost, said, “Let all the house of Israel therefore know assuredly that God hath made him both Lord and Christ, this Jesus whom you crucified.” Acts 2:36. Hence the apostles, almost exclusively, speak of Christ as Lord in connection with his second coming. This was their common name for Christ, and thus they recognized the glorious reward bestowed upon him for the salvation wrought for them, and the “all power” given unto him in heaven and earth.
3. It is as the Judge of the whole earth that he shall appear, both as Son of Man and as Lord; thus giving confidence to those who know him and have believed in him, and striking with terror those who have rejected his love.
4. He also comes as King to take final possession of his kingdom, to share its blessings and glory with all his willing subjects, and to inflict punishment upon all who have refused to have him reign over them.
Boyce, James (1887-06-01). Abstract of Systematic Theology (p. 341). . Kindle Edition.