First Question

We just finished John 8 in our Sunday morning studies.  One friend told me before the worship service that Jesus is Jehovah, the God of the Old Testament.  He expressed ideas like this post.

My friend told me I get the idea of the Trinity from Constantine and not from the Bible. 

He said there is a clear distinction between Jesus as Jehovah and His Father.  I smiled and agreed on this assertion after my polite disagreement over his first point.

But then I told him that in the Old Testament, there is clear distinction between Father as Jehovah and the divine Servant/Son.

Would you accept this latter biblical proposition?

Second Question

In looking at scripture text, I think amen is an attribute used equally of both Father and Son, but not for anyone else.  Do you? 

Third Question (Just for kicks)

“Verily, verily” – is this expression utilized by anyone other than Jesus Christ in LDS scriptures and commentary writings?