4. How did things begin to happen on that day of Pentecost just as Joel 2:28, 29 had foretold?

⁴ Things happened just as Joel 2:28, 29 foretold: the spirit-filled disciples began to prophesy, even in foreign languages, miraculously! Thousands of Jews who were in Jerusalem to celebrate the festival of Pentecost gathered to witness the spectacle. They heard the small congregation of Christ’s disciples “speaking,” as they said, “in our tongues about the magnificent things of God.”​—Acts 2:11.

 5. How did Peter use the first of the two “keys of the kingdom of the heavens” on that day of Pentecost?

⁵ In order to explain the occasion, the apostle Peter used the first of the two “keys of the kingdom of the heavens” by taking the lead in addressing the inquiring crowd. (Matthew 16:19) He bore witness to Jesus as the Messiah, the one rejected and killed by the Jewish leaders but resurrected on the third day and now glorified at God’s right hand.

For the promise [of Joel 2:28, 29] is to you and to your children and to all those afar off, just as many as Jehovah our God may call to him.”​—Acts 2:14-39.