All things are double one against another: and he has made nothing imperfect.
All Commentaries on Wisdom of Sirach 42:24 Go To Wisdom of Sirach 42
Given that "all things are in pairs, the one opposite the other," as Jesus the wise man says, receive what I send you according to the letter and according to the spirit, and consider that in every case the letter presupposes the intellect: without this, not even the letter would exist. Thus prayer also involves two ways, active and contemplative. And the same for numbers, which in an immediate way express quantity and in their deeper meaning quality.