@iclearwater,
Through a glass darkly is part of a famous verse in the King James Version of the New Testament of the Bible in English.
1 Corinthians Chapter 13 Verse 12
For now we see through a glass, darkly; but then face to face. Now I know in part; but then I shall know even as I am known.
St Paul is referring to how when living we can comprehend only a tiny amount of reality, as opposed to when we make it to the kingdom of heaven when we shall comprehend far more.