'Forever' in the Bible

I am the living bread that came down from heaven. If anyone eats from this bread he will live forever. The bread that I will give for the life of the world is my flesh."

This is the bread that came down from heaven; it is not like the bread your ancestors ate, but then later died. The one who eats this bread will live forever."

The slave does not remain in the family forever, but the son remains forever.

Then the crowd responded, "We have heard from the law that the Christ will remain forever. How can you say, 'The Son of Man must be lifted up'? Who is this Son of Man?"

Then I will ask the Father, and he will give you another Advocate to be with you forever --