How do we know the gift of the Holy Spirit is true?

The Holy Spirit's gift is rooted in the promise of Jesus in John 14:16, where He assures His disciples that the Comforter will come to them. This promise is reiterated in various passages throughout the New Testament, affirming the necessity of the Holy Spirit for the life of believers. Romans 8:9 states that if anyone does not have the Spirit of Christ, they do not belong to Him. The manifestation of the Holy Spirit in the lives of believers serves as a testament to the truth of this gift, confirming their adoption as children of God and enabling their growth in faith.