Mantra 7

आदित्प्रत्नस्य रेतसः ज्योतिः पश्यन्ति वासरम्; परो यदिध्यते दिवि ॥ ३.१७.७ ॥

In plain words

"Then they see the light of the ancient seed, which is kindled beyond, in heaven, the daylight."