What literary device is often used alongside the phrase "through a glass darkly"?

The phrase "through a glass darkly" is primarily recognized as a metaphor. This literary device compares the act of perceiving or understanding something to seeing through a dark or unclear glass, suggesting that one's view of reality is obscured or not fully clear. This metaphor invokes the idea that human understanding is limited and often clouded by illusions or misunderstandings.

Using a metaphor enriches the text by providing a deeper meaning that goes beyond the literal interpretation, evoking contemplation about the nature of perception and knowledge. Other literary devices listed do not capture this aspect as effectively. Irony involves a contrast between expectation and reality, personification attributes human characteristics to non-human elements, and simile uses "like" or "as" for direct comparisons, which is not applicable here. The metaphorical nature of the phrase is what makes it significant and powerful in literature.