Why did the Lord, as recorded by Matthew and Mark, tell His disciples, "I will go ahead of you to Galilee; there you will see Me" (Matt. 26:32; Mark 14:28), while Luke and John describe His appearance to them while they were still in a locked space? Apostolic testimony reveals that He also manifested to more than five hundred brethren, as well as to Peter and James (see 1 Cor. 15:5-7). Moreover, Luke, in the Acts of the Apostles, recounts that He was seen alive by the disciples after His suffering, presenting many convincing proofs and speaking to them about the kingdom of God (Acts 1:3). In sum, His appearances were frequent and to various disciples. Though Scripture does not detail the precise moments He was seen in Galilee, it does outline the day and hour of His manifestation in Jerusalem. He approached the disciples in their fear while they were in the locked house, and later, they journeyed to the Mount of Olives emboldened.
John notes that the disciples were assembled in the upper room, secured behind closed doors due to their fear of the Jews; Luke adds that there were more than just the eleven present. Matthew states that the eleven went into Galilee, to the mountain that Jesus had designated. Upon seeing Him, they worshipped Him; yet some doubted (Matthew 28:16-17). He empowered them to teach and baptize. Mark also mentions that at the conclusion, He appeared to the eleven disciples reclining at table and commanded them to proclaim the good news to all creation (see Mark 16:14-15).
The most straightforward explanation appears to be this: The Lord assured the disciples that they would encounter Him in Galilee, yet He first appeared to them in the upper room while they were still filled with fear. After this revelation, the eleven disciples, rejuvenated in spirit, set out for Galilee. It is also reasonable to think—an interpretation shared by many astute scholars—that there were fewer disciples in the upper room while a greater number gathered on the mountain.