तस्मादग्निः समिधो यस्य सूर्यः सोमात्पर्जन्य ओषधयः पृथिव्याम् ।पुमान् रेतः सिञ्चति योषितायां बह्वीः प्रजाः पुरुषात्सम्प्रसूताः ॥ ५ ॥
In plain words
From That comes Agni, whose fuel is the sun; from Soma comes the rain-cloud, and herbs grow upon the earth. The male sows his seed in the female: many are the offspring brought forth from the Puruṣa.
The commentators
Muṇḍakopaniṣadbhāṣyam
पञ्चाग्निद्वारेण च या ससरन्ति प्रजा , ता अपि तस्मादेव पुरुषात्प्रजायन्त इत्युच्यते—
तस्मात् परस्मात्पुरुषात् प्रजावस्थानविशेषरूप अग्नि । स विशेष्यते— समिधो यस्य सूर्य , समिध इव समिध , सूर्येण हि द्युलोक समिध्यते । ततो हि द्युलोकाग्नेर्निष्पन्नात् सोमात् पर्जन्य द्वितीयोऽग्नि सम्भवति । तस्माच्च पर्जन्यात् ओषधय पृथिव्या सम्भवन्ति । ओषधिभ्य पुरुषाग्नौ हुताभ्य उपादानभूताभ्य पुमानग्नि रेत सिञ्चति योषिताया योषिति योषाग्नौ स्त्रियामिति । एव क्रमेण बह्वी बह्व्य प्रजा ब्राह्मणाद्या पुरुषात् परस्मात् संप्रसूता समुत्पन्ना ॥
In plain words
The beings who pass through the five fires also arise from that very Puruṣa. The next verse declares—
From the supreme Puruṣa arises Agni as the heavenly realm, an abode for beings. Its fuel is the sun, for the sun kindles heaven just as fuel kindles an ordinary fire. Soma is produced in that heavenly fire; from Soma arises Parjanya, the rain cloud, which is the second Agni. From Parjanya come the plants that grow on earth. Eaten by a man, those plants are offered into the Agni of his body and become the material from which he pours seed into the Agni that is woman. Through this sequence, the many kinds of beings, beginning with brāhmaṇas, are born from the supreme Puruṣa.
Close to the Sanskrit
And it is taught that the creatures who move through the five fires are also born from this very Puruṣa—
From that supreme Puruṣa comes Agni in the particular form that is an abode for beings. It is qualified: “whose fuel is the sun.” It is fuel as ordinary fuel is, for the heavenly world is kindled by the sun. Then from Soma, which is produced from the fire of the heavenly world, comes Parjanya, the second Agni. From that Parjanya, plants arise upon the earth. The plants, having been offered into the Agni that is man and having become the material cause, are transformed as the man pours seed into the woman—that is, into the woman-Agni. In this sequence, the many beings, beginning with brāhmaṇas, are fully born from the supreme Puruṣa.