The Feast of Pentecost was already fulfilled.  And indeed, I see no scriptural proof that the Lord Jesus Christ will be fulfilling it again for a 2nd time.

THE SUMMER FEAST
THE FEAST OF PENTECOST: .......FULFILLED!

It was right on the Day of Pentecost, in the summer of the crucifixion year. Fifty days after the first fruits of the barley harvest had been waved at the Passover festivities that year it happened. That year in Jerusalem the Holy Spirit of YHVH-God fell in an unprecedented wave of glory. The outpouring began with the 120 in the upper room. This was the Congregation of believers in Jesus Christ who had been tarrying, waiting on God for the visitation that had been promised. The Holy Spirit fell upon the 120 as they gathered, all in one accord, in that upper room. The outpouring then spilled out into the streets of Jerusalem.

Pentecost in the New Covenant fulfillment was a life-giving flow. The Holy Spirit entered human hearts and lives on an individual basis. Pentecost in the Old Covenant had brought us the Torah, and the requirements of God. And on that first Pentecost when Moses brought down the Law to the Nation of Israel 3,000 died. But when Peter preached on Pentecost of that year YHVH-God did a new thing. 3,000 were saved. The infilling of the Holy Spirit brought new life in the God of Abraham, Isaac, and Jacob. The Holy Spirit outpouring continued in Jerusalem. But He did not stop there. This first Holy Spirit revival, (and let us not forget that it came out of the Jewish House of Judah in Israel), spread throughout Judea and on into Samaria, and beyond.

The prophet Joel spoke of this Holy Spirit outpouring upon the nations. (Joel 2:28-32) And the Apostle Peter made reference to it. (Acts 2) God's ministry of grace would go out beyond this initial Pentecostal outpouring. It would flow on into the gentile nations towards the ends of the earth. YHVH-God would be drawing all men to Himself. He would be doing this in the power of His Holy Spirit.

The prophet Joel saw the very same Holy Spirit outpouring that Peter saw on Pentecost Sunday 2,000 years ago. Peter makes a direct quotation of Joel's prophecy (Joel 2:28-32) in Acts 2. Joel saw the Holy Spirit outpouring that began that year at Pentecost. He saw it at its very peak. Joel saw it come to its final climax in the context of the final 6th seal cosmic signs of a darkened sun and a bloody moon. This is the End Time Revival.

Jesus/Yeshua tells us precisely when thiis main upthrust of the Pentecostal Holy Spirit outpouring will occur. He tells us quite clearly in the Olivet Discourse. He said that the days of the darkened sun and bloody moon would come "after the tribulation". (Mat.24:29) So we must assume that the cosmic signs are seen after the 1260 days of the Great Tribulation. The days of a darkened sun and a bloody moon will therefore be the 30 days extending out to day 1290 as referred to by the prophet Daniel. (Dan.12:11) We have good evidence that this day 1290, (numbered off after the Abomination of Desolation), will be the last day of this age, the final ultimate wrap-up, day of reckoning, day of accounting, Day of Atonement.

The Apostle Peter remarked on the awesome show of Holy Spirit power they were seeing at that time and put it in its over arching context. He said
"this is that which was spoken of by the prophet Joel".

Here is what happened on that awesome day.

ACTS 2
"And when the day of Pentecost was fully come, they were all with one accord in one place [together]. And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting. And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the Holy Spirit and began to speak with other tongues (or languages), 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 marveled, saying one to another, Behold, are not all these which speak Galileans? And how hear we every man in his own tongue, wherein we were born? . . . .And they were all amazed, and were in doubt, saying one to another, What meaneth this?" (Acts 2:1-12).

As we saw in the earlier articles the year of the crucifixion saw the first three spring feasts fulfilled. They erupted into holy history during passion week and right on schedule. So the Feast of Pentecost was the fourth celebration fulfilled that year. This auspicious Jewish holiday erupted that summer as a magnificent and memorable day in holy history. It saw the Congregation of Israel, (or Church), overflow its national banks, as it were, and flow out into the heathen nations. YHVH-God through His cosmic expression in His Son was doing a new work, just as He had promised through Isaiah several centuries before. YHVH-God is here speaking to His Servant.

6 Indeed He says,
'It is too small a thing that You should be My Servant
To raise up the tribes of Jacob,
And to restore the preserved ones of Israel; ......."

Here we see the extravagant grace of the God of Israel.
In effect He is saying that saving Judah and the lost ten tribes of Israel is "small potatoes".
He is going to go one better than that.
The Light of His salvation will shine forth out of Israel to the far side of the world.
Because He goes on to say,

"....... I will also give You as a light to the Gentiles,
That You should be My salvation to the ends of the earth.' "

The Day of Pentecost in that summer that followed the crucifixion was magnificent beyond description. It saw the first overflowing of the Holy Spirit into the gentile nations. This was an awesome day of visitation by the Spirit of Jesus Christ/Yeshua Hamashiach the Savior and Spirit of the Anointed One, the Messiah of Israel. This was the first day in which the Congregation, of Israel, (now expanded as the Church), went global. On that day the salvation of our Hebrew Messiah engulfed in Jerusalem in waves of glory and in great power. And so the Holy Spirit of YHVH-God went out among the people as Light to the gentiles. What a day that was!