Bede the Venerable — as excerpted in the Catena Aurea on Luke 2:42-50

“We may also say, that as by the seventh number, so also by the twelfth, (which consists of the parts of seven multiplied alternately by one another,) the universality and perfection of either things or times is signified, and therefore rightly from the number twelve, the glory of Christ takes its beginning, being that by which all places and times are to be filled.”