The baptism of the Holy Ghost is the birth of the Spirit (John 3:5). This spiritual baptism is necessary to put someone into the kingdom of God (God’s church, the bride of Christ) and is evidenced by speaking in other tongues (other languages) as the Spirit of God give utterance.
It was prophesied by Joel (Joel 2:28-29) and Isaiah (Isaiah 28:11), foretold by John the Baptist (Matthew 3:11), purchased by the blood of Jesus, and promised by Him to His disciples (John 14:26; 15:26). The Holy Ghost was first poured out on the Day of Pentecost upon the Jews (Acts 2:1-4), then upon the Samaritans (Acts 8:17), and later upon the Gentiles (Acts 10:44-46; 19:6). “The promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call” (Acts 2:39).