1 Corinthians 13:12

βλέπομεν γὰρ ἄρτι δι' ἐσόπτρου ἐν αἰνίγματι, τότε δὲ πρόσωπον πρὸς πρόσωπον: ἄρτι γινώσκω ἐκ μέρους, τότε δὲ ἐπιγνώσομαι καθὼς καὶ ἐπεγνώσθην.

1 Corinthians 13:12

For we currently see through a mirror in an enigma, but then, face to face.  I now partly know, but then, I will know thoroughly, even as I also am thoroughly known. 

δι' ἐσόπτρου: through a mirror.  In Paul’s time, mirrors were made from polished bronze or steel, not glass.

αἰνίγματι is the dative form of the word αἴνιγμα {ah'-ee-nig-ma}, which is where we get the word enigma.  In this passage, it is in a prepositional phrase preceded by ἐν [in], thus the dative form of the word.  An enigma is a statement whose meaning is hidden under obscure or ambiguous allusions, so that we can only guess at its significance; [New Oxford American Dictionary].

I chose the actual word enigma, instead of obscurity, for one reason/question: How much do we really know God?  He is so infinite that our minds could not possibly comprehend him.  We only get small insights into God when his Spirit moves in our lives.  That is a result of our limited, human body and mind.  He truly is an “enigma” to us.  With that said, he has given us just enough of him: not too little that we may not get a glimpse of him, and not to much as we may be overwhelmed by him.  Moses got so much of God that his face shined.  One day, our faces will also shine as His face shines!  Face to face!

A different take on the same thing

*Corinth was well known in the ancient world for producing some of the finest bronze mirrors available. Paul’s point in this analogy, then, is not that our current understanding and relationship with God is distorted (as if the mirror reflected poorly), but rather that it is “indirect,” (i.e., the nature of looking in a mirror) compared to the relationship we will enjoy with him in the future when we see him “face to face” (cf. G. D. Fee, First Corinthians [NICNT], 648)

*Taken from the translation notes of the NET Bible.