literal translation: forward and backward?

A couple of times the transliteration says something like "forward and backward are two-in-one". Comparing the subtitles and the dub in those places, it's clear the translators are not very successful right there despite straining hard. So just what are the literal Japanese words there?

(It feels to me like some kind of "proverb", and further one specific to Japanese culture with no reasonable English analogue. Is it? Is it perhaps the one sometimes transliterated as "The reverse side also has a reverse side"?)

What's the flavor the listeners are supposed to get?