Blessed is the faith of the simple shepherds. Although it found an infant wrapped in swaddling clothes it was not at all scandalized by them so as to refuse belief and think the less of him. Rather its devotion was increased so as to be more grateful for such condescension. For the more deeply humiliated and completely emptied out for them that majesty showed itself, the more easily and fully (if we wish to entertain a worthy opinion of them) love of him took possession of and claimed for itself the whole of their affections.
Brethren, you also will find today an infant wrapped in swaddling clothes and laid in the manger of the altar. Take care that the poverty of the covering does not offend or disturb the gaze of your faith as it beholds the reality of that august body beneath the appearance of other things. For as his mother Mary wrapped the infant in swaddling clothes, as our mother grace hides from us the reality of the same sacred body by covering it with certain outward appearances which are in keeping with the economy of salvation. So too mother wisdom covers the hidden majesty of the divine Word with riddles and figures, in order that in the one case the simplicity of faith and in the other the exercise of study may accumulate merit for itself into salvation.
Guerric of Igny, Liturgical Sermons I, Fifth Sermon for Christmas, v 4,5 (CF 8, p. 66)