Hello S Martin Shelton, thanks for taking the time to respond.

You said:

"I wonder. The four Gospels were written about one-hundred years after Jesus' death. And mostly written Greek. What language did Paul use?"

The Gospels were written far earlier than that, my friend.

Ireneaus records that Matthew wrote and published his Gospel while Peter and Paul were still alive and preaching the Gospel of Jesus in Rome.

All four Gospel authors and Paul wrote in Greek, as it was the common language at the time. Greek was so popular, even among Jewish people, that the entire Hebrew Scriptures were translated into Greek 200 years before Jesus was born, precisely because so many Jews were using Greek instead of Hebrew.