Hi,
Re: "Trinity"
That's not tough at all. The doctrine of the Trinity is found throughout Scripture, just not the term. For example, when Jesus was baptized, the Spirit descended "as a dove" and the Father spoke from heaven. So, the Trinity IS a Truth taught in Scripture.
And, yes, it is also a "great mystery" that God exists as one God in three Persons. Our minds cannot take in that wonderful mystery
So, I stand by my statement.
RE: "Unfortunately, lots of us would be like the early apostles, if we could, forbidding others, because they don't follow us.
Jesus did not advocate that."
I'm not sure what you mean by "forbid" others. But, it is clear that we cannot accept false teachings for ourselves. The challenge is to find the Truth.
Peace,
Fiosh