Pentacost Acts 2:1-7

 Acts 2:1 And when the day of Pentecost was fully come, they were all with one accord in one place.

Pentecost was a Jewish feast held fifty days after Passover; it was a time of celebration for the first-fruits of the harvest.

At Passover, the first sheaf to be reaped from the barley harvest was presented to God; but at Pentecost, the firstfruits of the wheat harvest were given to God. Therefore, Pentecost is called the day of firstfruits (Numbers 28:26) Also, Jewish tradition taught that Pentecost commemorates the day when the Law was given to Israel; the feast was sometimes called by the Jews shimchath torah, or "joy of the law"

So on Pentecost, Israel received the Law, and the Church received the Spirit of Grace in fullness

All in unity together seeking God.

Acts 2:2 And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting.

The word for Spirit is also "wind", a mighty rushing wind filling all the upper room. Is this the fan of Jesus separating the wheat from the chaff? Or is this a new life breathed into born again believers? Perhaps both and more.

Mat 3:11 I indeed baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall baptize you with the Holy Ghost, and with fire:
Mat 3:12 Whose fan is in his hand, and he will thoroughly purge his floor, and gather his wheat into the garner; but he will burn up the chaff with unquenchable fire.

Acts 2:3 And there appeared unto them cloven tongues like as of fire, and it sat upon each of them.

The baptism of fire as in Mat 3:11...he shall baptize you with the Holy Ghost, and with fire:

The idea behind the picture of fire is usually purification, as fire is used by a refiner to make pure gold, or as it can burn away that which is temporary, to leave that which is lasting. This is an excellent illustration of the principle that the filling of the Holy Spirit is not just for power, but for purity.

Under the New Covenant, the Holy Spirit rests upon God's people as individuals - the tongues of fire sat upon each of them.

Acts 2:4 And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.

How many were filled with the Holy Ghost and spake with other tongues? One hundred twenty were in one accord and were speaking in recognizable languages as the spirit gave them utterance.

tongues - the language or dialect used by a particular people distinct

utterances - to speak forth, speak out, say

Acts 2:5 And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven.
Acts 2:6 Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language.

A crowd quickly gathered, being attracted by this sound (either the rushing mighty wind or the speaking in other tongues); when they came they heard the Christians speak in their own foreign languages; apparently the Christians could be heard from the windows of the upper room, or they went out onto some kind of balcony or into the temple courts.

What better way to show the presence of Gods Spirit in the hearts of the people, then to speak edifying words of God in each language. This was a reversal of what happened at the tower of Babel. There all were confounded and confused speaking in languages no one understood.

Acts 2:7 And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans?

Galileans were not known to be educated men or good speakers.