After Jesus' death, burial and resurrection the disciples went to Jerusalem to ' wait for the promise of the Father'. On the day of Pentecost that event occurred. Devout Jews were gathered in Jerusalem for the feast of Pentecost. The disciples received the Holy Ghost, the Jews marvelled , Peter told them about Joel's prophesy, they believed and over 3000 souls received the Holy Ghost that day. It is a promise to all who the Lord calls. God's kingdom is a spiritual kingdom. All his subjects are governed by the power of the Spirit, that transforms the human nature and renews our minds. So yes, it is necessary to receive the Holy Ghost. It still happens in this 21st century.
