NT Scripture was not yet known at Pentecost.
It's not as simple as you want it to be.
But, that does not mean that God can not make it simple for you...
If you are willing to grow.
It is simple when you have the keys. Ezekiel prophesied under the Babylonian captivity. Every bit of what he prophesied was fulfilled on the day of Pentecost. You can't realistically deny that all of these things happened. This was the day the sticks of Ephraim and Judah were joined together as one in the lord's hand
For I will take you from among the heathen, and gather you out of all countries, and will bring you into your own land. Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you. A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh. And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them. And ye shall dwell in the land that I gave to your fathers; and ye shall be my people, and I will be your God. Ezekiel 36:24-28
And when the day of Pentecost was fully come, they were all with one accord in one place. Acts 2:1
And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. Acts 2:5
But Peter, standing up with the eleven, lifted up his voice, and said unto them, Ye men of Judaea, and all ye that dwell at Jerusalem, be this known unto you, and hearken to my words: Acts 2:14
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: Acts 2:22
Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls. Acts 2:41