the Holy Ghost.

Acts 2:2-4
Suddenly a sound like a mighty rushing wind came from heaven and filled the whole house where they were sitting. . . .

Acts 4:31
After they had prayed, their meeting place was shaken, and they were all filled with the Holy Spirit and spoke the word of God boldly.

Acts 8:15-17
On their arrival, they prayed for them to receive the Holy Spirit. . . .

Acts 11:15
As I began to speak, the Holy Spirit fell on them, just as He had come upon us at the beginning.

Acts 19:6
And when Paul laid his hands on them, the Holy Spirit came upon them, and they spoke in tongues and prophesied.