Zachariah's Doubts

Quod ubi Zacharias, fratres, audivit, tantum se meruisse suis precibus sacramentum, rei ipsis consideratione territus, sacramenti ipsius aestimatione turbatus, nec se mereri tantum credidit, et Deum dubitatvit ad haec talia et tanta descendere. Hinc est quod dicit: 'Unde hoc sciam? Ego enim senex sum, et uxor mea processit in diebus suis.' Hoc est dicere, quomodo me habere filium ratio non permittit humana, ista nasci et mori Deum majestas non sinit sempiterna. Cui angelus veniabiliter non credenti peonam signi tantum dedit, non perfidiae: cautelae est tarde de Deo humilia credere, de Deo tardius conumeliosa sentire. Sanctus Petrus Chrysologus, Sermo XC

But, brothers, when Zachariah heard that he had merited so great a mystery by his prayers, he was terrified when he considered the matter, he was troubled by the thought of this mystery, for he did not believe he merited something so great, and he doubted that God was coming down for such momentous things, which is why he says, ' How may I know this? I am an old man, and my wife is advanced in her days.'1 Which is to say, as human nature does not allow me to have a son, so God's eternal majesty does not allow him to be born and die. This lack of belief being a venial matter, the angel gave him a punishment that was only a sign of doubt, not of faithlessness, of the caution of being slow to believe humble things of God, and to be slower to think dishonourably of God. Saint Peter Chrysologus, Sermon 90 1 Lk 1. 18