Q&A: Is the God of Islam the same as the God of Christianity?

Winger's response: Ask the person why they think they are the same — put the burden of proof on them. Then refer to Alan Shlemon from Stand to Reason, who has done detailed work comparing the attributes of Allah in Islam to the God described in the Bible. The request for "non-biased secular proof" is dismissed as silly — a non-Christian and non-Muslim commentator has no special epistemic advantage over someone who has studied both traditions. What you want is informed adherents speaking openly and honestly about their own traditions.