I think the crucial point of disagreement was made very clear in the point of the debate at which Andy asked Jeff (at about 43:30 in the YouTube video): "What is the foundation of your faith? Why do you believe what you believe?" Jeff, in his typical quick and confident manner, replied: "The Word of the Living God!" Andy apparently wasn't adequately prepared to reply to this answer and responded with a weak, "Ok...". (It is even worse if you are watching the YouTube video because he follows up with a shoulder shrug and a smirk...)
I wish to briefly share my thoughts on one thing I believe to be a crucial component [of debate]. What is that one thing? In a word, humility.
A natural consequence of human existence is disagreement. Each of us tend to have opinions or beliefs as to the truth on any matter in question. Our interactions with others almost inevitably reach some contention as it is often the case that individuals have different beliefs and opinions on the same matter.
Arguments are necessarily appeals to authority. When we make an argument in a debate, we inevitably appeal to some authority to validate our claim, whether it be a person, a publication, or propaganda!