I don't know how Justin Brierley does it, but he gets the most fantastic guests on his show Unbelievable. In this clip from a forthcoming episode, Tom Holland explains to Tom Wright why he changed his mind about Christianity: specifically, how he came to realise that his assumptions about liberty, equality, human rights, international law and the like do not trace their roots to Greek or Roman concepts, as he had previously thought, but rather to the influence of Christian thinking, and that of Paul in particular. It's a wonderfully concise and eloquent explanation, both in what Holland says about the Greco-Roman world and in what he says about Paul, and you can watch it all in four minutes: