Tóibín has approached the life of Jesus from a new angle, that of his mother Mary. As his mother she is far more interested in her son’s safety than in him being the saviour, and in how his friends lead him astray than what he is responsible for.
I’m never quite sure about men writing novels aiming to capture such a female experience as motherhood, but Tóibín does well. His Mary is emotional without being overly sentimental, and strong in her own way. But she still frames herself against the (absent) men in her story. Women are not a frame, and he doesn’t quite get that concept. Of course the point is the gospel, in which the character herself is not the point, but she does not focus purely on her child.
There is little new here. Of course the story is known, and the concept of it as a tragedy is also unexpected. So there ends up being little new here except a minor reframing. It doesn’t explain why this was shortlisted for the Man Booker prize.