अयमनिवैश्वानरो योऽयमन्तः पुरुषे येनेदमन्नं पच्यते यदिदमद्यते तस्यैष घोषो भवति यमेतत्कर्णावपिधाय शृणोति स यदोत्क्रमिष्यन्भवति नैनं घोषँ शृणोति ॥ १ ॥
In plain words
This fire is Vaishvanara — the one burning inside you, digesting whatever food you eat. It makes a sound of its own, and you can hear it if you cover both ears. But when you are about to leave this body, that sound falls silent — you no longer hear it.
Close to the Sanskrit
This fire is Vaiśvānara, which is this one within a person, by which this food that is eaten is digested. Of it, this is the sound that one hears having covered these two ears. When he is about to depart, he does not hear this sound.