In plain words
The eye takes in every light, the sun, the fire. The mind is the eye behind that eye. And behind the mind is the reality that sees through it. When one knows for certain 'that am I', what bliss there is! Hari, salutation to Nārāyaṇa.
Word for word
When one becomes certain that one is oneself the reality that was the eye to the eye which is the mind, itself the eye to the eye that grasps every light such as the sun and fire, what bliss! Hari, salutation to Nārāyaṇa.