The promise of sending the Holy Spirit(Pentecost) was fulfilled in

The promise of sending the Holy Spirit was fulfilled in Jerusalem. After Jesus ascended into heaven, He instructed His disciples to wait in Jerusalem until they received the promised Holy Spirit. On the day of Pentecost, which was a Jewish holiday, the disciples were all gathered together in one place when suddenly a sound like a rushing wind filled the room, and tongues of fire appeared and rested on each of them. They were all filled with the Holy Spirit and began speaking in different languages, which amazed the crowds of people who had gathered in Jerusalem from all over the world. This event marked the beginning of the Church and empowered the disciples to go out and spread the message of Jesus to the world. The Holy Spirit gave them the courage, wisdom, and supernatural abilities to perform miracles and preach with authority. This event is celebrated by Christians every year as the Feast of Pentecost or the Birthday of the Church.