Now

"Now" marks John's summary statement about the attitude of the Jewish leaders toward Jesus. (See: rc://en/ta/man/translate/writing-background)

is working

This refers to doing labor, including anything that is done to serve other people.

Here "the Jews" is a synecdoche which represent the "Jewish leaders." AT: "the Jewish leaders" (See: rc://en/ta/man/translate/figs-synecdoche)

"saying that he was like God" or "saying that he had as much authority as God"