What scripture do I use? I've already given you quite a few verses, but I'll suffice with this one.
There is also an abundance of circumstantial evidence which I've already provided.
1 Corinthians 13:8 said:
Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away.
Now for the third question..."I will ask you again...who were the ones speaking too on the day of Pentecost?"
If I'm understanding your question correctly....we see the disciples speaking in languages that were not their native Galilaean tongue. The Parthians heard them speak in the Parthian tongue. The Medes heard them speak in the Mede tongue...and on and on. Each listener heard his own language being spoken. That was a miracle. God translated just like the UN does when they sit around with those little microphones in their ears. Only in this case, it was the Holy Spirit. Now that's a miracle that cannot be replicated by any man.
[quote="Acts 2:4-12":3bwym5vz]And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance. And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language. And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans? And how hear we every man in our own tongue, wherein we were born? Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in Judaea, and Cappadocia, in Pontus, and Asia, Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes, Cretes and Arabians, we do hear them speak in our tongues the wonderful works of God. And they were all amazed, and were in doubt, saying one to another, What meaneth this?