There are three great areas of salvation. There is basic salvation through the blood of the cross. There is Pentecost. Then there is the climax in which God and Christ find Their rest through the Church.
Three times a year all your men must appear before the Lord your God at the place he will choose: at the Festival of Unleavened Bread (Passover) the Festival of Weeks (Passover), and the Festival of Tabernacles. No one should appear before the Lord empty-handed. (Deuteronomy 16:16)
This is why people from so many different nationalities were present in Jerusalem, as described in the second chapter of the Book of Acts. They were obeying the command to assemble in Jerusalem during the Festival of Pentecost.
Pentecost, meaning "fifty," is so named from the fact that it was celebrated fifty days after the Festival of Unleavened Bread.
A few years after I had been saved I enrolled in an Assemblies of God Bible school in San Diego, California, named "Berean." I knew nothing whatever about the Pentecostal movement, having been raised in a non-Christian home in Connecticut. But the Lord saved me and called me to preach while in the Marine Corps, in about 1945, in Sasebo, Japan.
The reason I enrolled in Berean (Yale Theological Seminary in New Haven would have been my preference), was that all the schools were filled because of the glut of veterans newly discharged from the service. I am referring to 1946.
I knew nothing at all about the baptism with the Holy Spirit including speaking in other languages. I do not like to use the word "tongues," which means "languages," because there has been so much opposition about "tongues" it has sullied the term in my mind. I prefer the tem "languages" and often use it in place of "tongues."