‘Be it done to me according to your word’, says the Blessed Virgin Mary, about to become Theotokos. She shows us what it means to walk, in St Paul’s phrase, ‘by faith, not by sight’ (2 Cor 5:7). St Ambrose expresses this in different terms:

Incomprehensibilis incomprehensibiliter operabatur in Matre.

Which is to say that ‘the Unfathomable worked unfathomably in his Mother.’ We have limited tolerance, now, for what is incomprehensible. We like things to be clearcut, simply expressed, horizontal, ideally risk-free. We’ve a massive act of renunciation to make if we would enter the Mystery of Faith and make our home within it.