The works of Ādi Śaṅkarācārya

Praśnottararatnamālikā

Verse 22

कोऽन्धो योऽकर्यरतः को बधिरो यो हितानि न शृणोति ।को मूको यः काले प्रियाणि वक्तुं न जानाति ॥ २१ ॥

In plain words

Who is blind? The one who loves doing what should never be done. Who is deaf? The one who will not hear what is good for him. Who is mute? The one who does not know how to say the kind thing when the moment comes for it.

Close to the Sanskrit

Who is blind? He who is devoted to what ought not to be done. Who is deaf? He who does not hear beneficial things. Who is mute? He who does not know how to speak pleasing words at the right time.