The lamp of the body

The word translated "sound" is haplous: single, simple, undivided. An eye that looks at one thing at a time. When attention is single, Jesus says, the whole body fills with light. Not the mind only; the body. Awakening is physical.

Compare the divided eye, the attention that is always half elsewhere, scrolling while eating, planning while listening. That eye lets in no light because it never rests anywhere long enough for light to enter. Every practice on this site is, at bottom, training for the single eye: one breath, one word, one meal at a time, one person in front of you.