en_tn/luk/22/59.md

insisted and said

"said insistently" or "said loudly"

Truly this man

Here "this man" refers to Peter. The speaker probably did not know Peter's name.

he is a Galilean

The man could probably tell Peter was from Galilee from the way he talked. (See: rc://en/ta/man/jit/figs-explicit)