Start by affirming Truth exists and should be pursued. That means there must be a way to find it reliably despite our faulty sensors. That way is Spirit. It's not enough just to make a factually true statement, it's also necessary not to be using it in a deceptive spirit.

Everyone knows what it's like to speak honestly, they know when someone is speaking in truth and in spirit. Because of this, when we're dealing with truth statements, we can work together pursuing the truth and arrive at the same place because we are pursuing it in the same spirit. That's the resolution of all contradiction.

If there's no Truth to start out with, there's no point in saying or doing anything, because it's the same as not saying or doing. But everyone believes there's a point, so everyone ultimately believes there's a Truth worth working for. When you commit to pursuing Truth, you find it, that's how the universe works. Eventually we find that there's a community of Truth seekers that has greater solidity and history than any other, they have a book they've checked for millennia and found it to have greater communicative value and description of reality than any other, and the independent evidence for this Holy Bible being the book of Truth continues to grow until you see the whole big picture. That's the unity of the good news, everyone comes to the same core message for humanity who looks for it. Remaining disagreements are just about semantics and technicalities. If there's a true binary contradiction between two people, it's because they're not in the same spirit.