Yes, it really is something new!

[T]he consistent line taken in the various texts that make up the New Testament and that came to be affirmed with growing force as representative of emergent “proto-orthodox” Christianity was a rather exclusive one: believers were to abstain from the worship of any of the deities of the Roman world except the one God of biblical tradition and God’s Son, Jesus. To judge from the frequent complaints about the matter by pagan observers and critics noted in an earlier chapter, it does seem that at least most Christian believers did so. In the dominant sort of early Christian teaching, believers were to base their religious life entirely on their relationship with this one deity and their participation in Christian conventicles. Matching their exclusive worship practice was what we can term an exclusive religious identity. In this, I submit, we have a new kind of religious identity that is very different from what was typical of the Roman period.— Destroyer of the gods: Early Christian Distinctiveness in the Roman World, page 89