the burden of proof lies with the one who speaks, not the one who denies) is the obligation on a party in a dispute to provide sufficient warrant for its position.
Flying Squid said it is impossible what is described in the bible. So he or you if you take his side are the one burdened with proof. In fact the bible provides a very straightforward reasoning. Jesus was granted the power to do wonders by God so people would recognize him as a messenger of God and listen to him spreading the message of God.
You can say you dont believe in that. But it is not a proof of it not having happened. Especially as a lot of people who lived at the time said otherwise.