When someone asked me what religion I was I would say "I'm a Jehovah's Witness." So many others including my ex wife would say "I'm ONE of Jehovah's Witnesses." I could never figure that out. They would make such a point of saying "one of...." What's up with that?
I always wondered why
They are word playing on strength of numbers. It's a concise way of saying "We are many" without sounding like the Borg from Star Trek.
Change "Jehovah" to "God".
Now it sounds strange to say, "I am God's witnesses." It's more accurate to say, "I am one of God's witnesses."