Bhashya
कस्मादेवम्? यस्मात्तस्य ह वै प्रकृतस्यैव एतस्य आत्मनो वैश्वानरस्य मूर्धैव सुतेजाः चक्षुर्विश्वरूपः प्राणः पृथक्-ग्वर्त्मात्मा संदेहः बहुलो वस्तिरेव रयिः पृथिव्येव पादौ ।अथवा विध्यर्थमेतद्वचनम्—एवमुपास्य इति ।अथेदानीं वैश्वानरविदो भोजनेऽग्निहोत्रं संपिपादयिषन् आह— एतस्य वैश्वानरस्य भोक्तुः उर एव वेदिः, आकारसामान्यात् ।लोमानि बर्हिः, वेद्यामिवोरसि लोमान्यास्तीर्णानि दृश्यन्ते ।हृदयं गार्हपत्यः, हृदयाद्धि मनः प्रणीतमिवान्तरी भवति ; अतोऽन्वाहार्यपचनोऽग्निः मनः ।आस्यं मुखमाहवनीय इव आहवनीयो हूयतेऽस्मिन्नन्नमिति ॥
In plain words
Why is this? Because the head of this very Vaiśvānara—the Self under discussion—is the radiant Sutejas, His eye is the all-formed Viśvarūpa, His breath is the multi-pathed Prāṇa, His trunk is the vast middle, His bladder is wealth, and the earth itself is His two feet. Alternatively, this statement is an injunction instructing us to meditate upon Him thus. Now, wishing to show that eating for one who knows Vaiśvānara is itself an Agnihotra sacrifice, the text explains: For this enjoyer Vaiśvānara, the chest is the sacrificial altar, because of its shape. The body hairs are the sacred grass, for they appear strewn on the chest just as grass is spread on an altar. The heart is the Gārhapatya fire, because the mind seems brought forth from the heart; and thus the mind serves as the southern Anvāhāryapacana fire. The mouth is like the Āhavanīya fire, because food is poured into it as an oblation.
Close to the Sanskrit
From what? Because of that very treated self of Vaiśvānara, the head indeed is Sutejas, the eye is Viśvarūpa, the breath is Prāṇa whose path is separate, the trunk is the middle body, the bladder indeed is Rayi, the earth indeed is the two feet. Or else this utterance is for the purpose of injunction—thus he is to be meditated upon. Now then, wishing to establish the Agnihotra in the eating of the knower of Vaiśvānara, he says: Of this Vaiśvānara the enjoyer, the chest indeed is the altar, due to similarity of shape. The hairs are the sacrificial grass, hairs are seen strewn on the chest as if on an altar. The heart is the Gārhapatya fire, for the mind is brought forward as it were from the heart; hence the Anvāhāryapacana fire is the mind. The mouth is the face, like the Āhavanīya fire, food is sacrificed in this Āhavanīya fire.