It's a controversial idea that will undoubtedly trigger those with a thin skin but what if the Bible was never meant to be universalist? What if most mainstream churches—Catholic, Orthodox and Protestant—incorrectly interpret the Great Commission?
Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.
—Matthew 28:19 (KJV)
After all, it's quite clear, right?
Well, that depends.

It's not something that I considered until recently but there is actually a pretty good argument to be made that the meaning of 'nations' in the Bible is a case of lost in translation.
The word 'nation' comes from the Greek 'ethnos', translated as 'gentile' in the New Testament and now largely meaning 'non-Jew' (or Christian). I mean, that's what I was taught too.
But William makes the point that 'gentile' is an empty word and is incorrectly used by many churches.
Depending on the context, it can refer to the nations in Genesis 10 or the northern tribes of Israel who were to be grafted back into the olive (or fig) tree that is Israel.
It doesn't necessarily refer to the whole world.

What about John 3:16?
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
The word 'world', when translated from Greek, can mean a few things:
- system (ordered arrangement or structure)
- universe (the entirety of existence)
- worldly affairs
- the inhabitants of the world
It's important to remember that the original scriptures were not written in English but in Hebrew (with some Aramaic) and later in Greek and other languages. The Old Testament was primarily Hebrew and the New Testament was primarily Greek.
Also, consider that Jesus came to reunite the lost tribes of Israel.
'But he answered and said, I am not sent but unto the lost sheep of the house of Israel.'
—Matthew 15:24 (KJV)
Hang on.
If Christianity isn't meant for everybody, then who is it meant for and who are the lost sheep (tribes) of Israel?
I find this a genuinely fascinating topic and I urge you to listen to my conversation with biblical scholar William Finck, of Christogenea.org, who has a gigantic archive including a huge video series called 100 Proofs The Israelites Were White.
Why does any of this matter?
William answers that below.