The Old Testament prophets looked forward to a day when God’s Spirit would dwell within His people (Jer 31:31-34; Ezk 36:22-27), and they would become prophets (Joel 2:28-32). When the Messiah arrived, God would enter into a “new covenant” with His people (Jer 31:31). On the night in which He was betrayed, Jesus lifted the cup and said, “This cup which is poured out for you is the new covenant in My blood” (Lk 22:20). By this statement He was revealing that His death on the cross would bring this great promise to His followers. After His resurrection He commanded His disciples to wait for this promise to arrive. He said they would be “baptized in the Holy Spirit…” (Ac 1:4, 5), and by that baptism He said they would receive the power they would need to be His witnesses (Ac 1:8). This promise arrived on the Day of Pentecost (Ac 2:1-4; 14-21), and continues to be given by God to every person who repents and believes in Jesus Christ for the forgiveness of sins (Ac 2:38, 39).