Mark 16:19

This event happened 40 days after the appearances that the writer just recorded (cf. Acts 1:3). He narrated the ascension and session of Jesus simply. The title "Lord Jesus" occurs only here and in Luke 24:3 in the Gospels. Jesus of Nazareth became Lord to His disciples, in the sense of sovereign master, following His resurrection. He was that always, but the Resurrection taught the disciples that that is what He was.

Jesus had predicted His ascension in veiled terms (Mark 14:7). The disciples witnessed this. They did not witness His seating in heaven. The Old Testament anticipated Messiah’s seating in heaven before His return to reign (Psalms 110:1). The disciples learned that that session would occur between Jesus’ two advents, not before His first advent (cf. Acts 2:33-35; Acts 7:56). Jesus’ present seated position at the Father’s right hand pictures His finished work on earth for the time being and His authority as the executor of God’s will now. Jesus’ present rule over the church from His Father’s right hand in heaven is not the same as His future rule over the Davidic kingdom from David’s throne on earth. [Note: See Cleon L. Rogers Jr., "The Davidic Covenant in Acts-Revelation," Bibliotheca Sacra 151:601 (January-March 1994):81-82.]