Waiting is often difficult, especially if we think we know what should be done and when. The disciples were excited and relieved that Jesus was alive again; surely He would now overthrow His enemies and become the King of Israel. They had small ambitions, to be senior officials in Jesus' government in Jerusalem. But Jesus knew God's master-plan; it was much bigger, would be achieved very differently and to a different timetable (

Jesus had told the apostles to wait in Jerusalem until the Holy Spirit came upon them (Acts 1:4-5). So after He had ascended into heaven they obeyed. Walking the kilometre from the Mount of Olives they reached the upper room, inside the city, where they were staying.

Peter was concerned that the absence of Judas Iscariot, who died after betraying Jesus, would frustrate Jesus' plans. Gathering about 120 believers, including his fellow apostles, Peter invited them to choose a replacement. However this was not just a matter of voting for friends; it was treated as a very serious matter. The man must have known Jesus and have been a part of His 'team' all the time from the time John baptised Him until His ascension. The chosen man must also have personally encountered Jesus after the resurrection.

Pentecost was one of the three great Jewish pilgrim feasts. All able bodied men were expected to come to Jerusalem, from wherever they lived, for the festival. The word 'Pentecost' is of Greek and Latin origin – used by the church as it was the fiftieth day after Easter Sunday (1 Corinthians 16:8).