What did Peter associate Joel's promise with?

Peter associated Joel's promise with the extension of the gospel, as seen in Acts 2 during the Pentecost sermon. In this sermon, Peter quotes the prophet Joel from the Hebrew Scriptures, highlighting the outpouring of the Holy Spirit on all people. This event marks a pivotal moment in the early Church, where the Spirit empowers believers to spread the message of Jesus Christ far and wide. The fulfillment of Joel’s prophecy serves as a foundation for the mission of the Church, emphasizing that the gospel is for everyone, transcending cultural and social boundaries. This focus on the gospel's extension aligns with the vision of the Church's growth and the call to make disciples of all nations, illustrating the transformative and inclusive nature of the Christian faith initiated by Peter's preaching and the events of Pentecost.