Peter, who preaches to the crowds in Jerusalem at Pentecost, certainly was slow to understand. He speaks forcefully at Pentecost, forty days after the Passover when Jesus died and rose from the dead, but the days before he’s speechless. It took awhile for him and for the others who came up with Jesus from Galilee to learn and be enlightened about this great mystery..
Mark’s accounts of Jesus resurrection appearances, read on the Saturday of Easter week, stresses the unbelief of his disciples. They were not easily persuaded.
For this reason, each year the Lord refreshes our faith in the resurrection, but it’s not done in a day. We need time to take it in, like the first followers of. Jesus, and for that we have an easter season of forty days. Just for starters.
The disciples are slow to understand the mission they’re to carry out because it’s God plan not theirs, a plan that outruns human understanding. A new age had come, the age of the Holy Spirit, and they didn’t understand it. The fiery winds of Pentecost had to move them to go beyond what they see, beyond Jerusalem and Galilee to the ends of the earth.
The Holy Spirit also moves us to a mission beyond our understanding. Luke says that in the Acts of the Apostles. “The mission is willed, initiated, impelled and guided by God through the Holy Spirit. God moves ahead of the other characters. At a human level, Luke shows how difficult it is for the church to keep up with God’s action, follow God’s initiative, understand the precedents being established.” (Luke Timothy Johnson, The Acts of the Apostles)
“You judge things as human beings do, not as God does,” Jesus says to Peter elsewhere in the gospel. We see things that way too.
Peter’s slowness to follow God’s plan remained even after Jesus is raised from the dead. He doesn’t see why he must go to Caesaria Maritima to baptize the gentile Cornelius and his household. (Acts 10,1-49) It’s completely unexpected. Only gradually does he embrace a mission to the gentiles and its implications. The other disciples are like him; God’s plan unfolds but they are hardly aware of it.
One thing they all learned quickly, though, as is evident in the Acts of the Apostles. Like Jesus, they experience the mystery of his cross, and in that experience they find wisdom.