Acts 1:8
But you will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem and in all Judea and Samaria, and to the end of the earth.”
Acts 4:31
And when they had prayed, the place in which they were gathered together was shaken, and they were all filled with the Holy Spirit and continued to speak the word of God with boldness.
John 15:26-27
“But when the Helper comes, whom I will send to you from the Father, the Spirit of truth, who proceeds from the Father, he will bear witness about me. 27 And you also will bear witness, because you have been with me from the beginning.
The true biblical sign of the Baptism of the Holy Spirit is – an emboldened witness of Jesus.
Whether by the means of tongues, prophecy, or preaching the Holy Spirit came to empower the church to witness to Jesus.