According to Acts 2 it was the Holy Spirit that was present at Pentecost, but the prophecy of Joel doesn't match what happened there, and Peter confused the Messiah with YHWH just like Paul did in Romans and Philippians.
Acts 2
21 And it shall come to pass, that whosoever* shall call on the name of the Lord shall be saved.
22 Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know:
25 For David speaketh concerning him, I foresaw the Lord always* before my face, for he is on my right hand, that I should not be moved:
And it shall come to pass, [that] whosoever shall call on the name of YHWH shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as YHWH hath said, and in the remnant whom YHWH shall call.
Joel 2:32
I have set YHWH always before me: because [he is] at my right hand, I shall not be moved.
Psalms 16:8
Acts 2
21 And it shall come to pass, that whosoever* shall call on the name of the Lord shall be saved.
22 Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know:
25 For David speaketh concerning him, I foresaw the Lord always* before my face, for he is on my right hand, that I should not be moved:
And it shall come to pass, [that] whosoever shall call on the name of YHWH shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as YHWH hath said, and in the remnant whom YHWH shall call.
Joel 2:32
I have set YHWH always before me: because [he is] at my right hand, I shall not be moved.
Psalms 16:8