How do we know the Holy Spirit is necessary for salvation?

As Paul articulated in Acts 19, he asked certain disciples, 'Have you received the Holy Ghost since you believed?' (Acts 19:2). This question underscores the necessity of the Holy Spirit in the life of a believer. The Spirit is the one who reveals Christ to us and enables our faith. In John 3:8, it is said, 'The wind blows where it wishes, and you hear the sound of it, but cannot tell where it comes from and where it goes. So is everyone who is born of the Spirit.' This illustrates that regeneration, the rebirth required for faith, is solely the work of the Holy Spirit. Therefore, without the Spirit's revealing and regenerating work, no one can believe in Christ.