RobH_en_tn/mat/09/03.md

Behold

This marks the beginning of another event in the larger story. It may involve different people than the previous events. Your language may have a way of doing this.

among themselves

Possible meanings are 1) each one was thinking to himself, or 2) they were speaking among themselves.

blaspheming

Jesus was claiming to be able to do things the scribes thought only God can do.