What does Mark 14:28 mean?

Jesus is telling the disciples where to find Him after they abandon Him. He isn't talking about being raised up onto the cross, for which He has used the phrase "lifted up." Here, He means being resurrected. When the women go to the tomb to prepare Jesus' body, they meet an angel who reiterates Jesus' command to meet in Galilee (Mark 16:7). After the crucifixion, they are so afraid of the Jewish leaders they forget these words and hide in a locked room (John 20:19). As a result, Jesus visits them in and around Jerusalem, first.

Shortly after Mary Magdalene hears the message from the angel, Jesus, Himself, appears to her (John 20:1–18). That day, Jesus meets two disciples traveling to Emmaus, about seven miles west of Jerusalem (Luke 24:1–35). One of them is Cleopas, and the other is unnamed, so it's unlikely they were part of the Twelve. Later that evening, Jesus appears to all the disciples but Thomas in a locked room (John 20:19–23). Eight days after this, He again meets with them with Thomas present (John 20:24–29).

We don't know where the two visitations occurred, but they were probably close to Jerusalem because the disciples were afraid of "the Jews," a euphemism meant to mean the Jewish religious leadership. Later, however, Jesus meets with seven of the disciples on the Sea of Tiberias, otherwise known as the Sea of Galilee (John 21). While there, Jesus restores Peter (John 21:15–19).

In the days after the resurrection, both John (John 20:30–31) and Luke (Acts 1:3) note that Jesus provides extensive proof that He has risen from the dead. He appears to many of His followers, including a single group of more than five hundred (1 Corinthians 15:5–7). After forty days, when Jesus and the disciples return to the Jerusalem area, Jesus takes the disciples to the Mount of Olives (Acts 1:12) near Bethany (Luke 24:50), where He ascends into heaven (Acts 1:6–11).