The apostles had been in hiding for forty days. This day happened to be the Jewish festival of Pentecost, and thousands of visitors from all parts of the world were in Jerusalem. Many arrived for this feast, but a majority had tarried in the city since the Passover. Now these frightened apostles emerged from their weeks of seclusion to appear boldly in the temple, where they began to preach the new message of a risen Messiah. And all the disciples were likewise conscious of having received some new spiritual endowment of insight and power.
It was about two o’clock when Peter stood up in that very place where his Master had last taught in this temple, and delivered that impassioned appeal which resulted in the winning of more than two thousand souls. The Master had gone, but they suddenly discovered that this story about him had great power with the people. No wonder they were led on into the further proclamation of that which vindicated their former devotion to Jesus and at the same time so constrained men to believe in him. Six of the apostles participated in this meeting: Peter, Andrew, James, John, Philip, and Matthew. They talked for more than an hour and a half and delivered messages in Greek, Hebrew, and Aramaic, as well as a few words in even other tongues with which they had a speaking acquaintance.
The leaders of the Jews were astounded at the boldness of the apostles, but they feared to molest them because of the large numbers who believed their story.
By half past four o’clock more than two thousand new believers followed the apostles down to the pool of Siloam, where Peter, Andrew, James, and John baptized them in the Master’s name. And it was dark when they had finished with baptizing this multitude.
Pentecost was the great festival of baptism, the time for fellowshipping the proselytes of the gate, those gentiles who desired to serve Yahweh. It was, therefore, the more easy for large numbers of both the Jews and believing gentiles to submit to baptism on this day. In doing this, they were in no way disconnecting themselves from the Jewish faith. Even for some time after this the believers in Jesus were a sect within Judaism. All of them, including the apostles, were still loyal to the essential requirements of the Jewish ceremonial system.