Between the old and new testament there is a 450 year period called the intertestamental period where god spoke to no one. There are a number of Jewish writing debating these odd passages in the old testament. How does god speak to speak? do we have one god or two gods etc etc. Strict monolistic Jews were not very comfortable with some of the passages in the scrolls because it made them look like pagans.
The general idea after the new testament was written was the visible manifestions of god in the old testament were actually Jesus Christ.
I can't put a neat little bow around it but when John wrote the word was god, that' what he meant.