Shat.Upa 01.09

मासो वै प्रजापतिः। तस्य कृष्णपक्ष एव रयिः। शुक्लः प्राणस्तस्मादेते ऋषयः शुक्ल इष्टिं कुर्वन्तीतर इतरस्मिन्। अहोरात्रे वै प्रजापतिः। तस्याहरेव प्राणो रात्रिरेव रयिः। प्राणं वा एते प्रस्कन्दन्ति ये दिवा रत्या संयुज्यन्ते। ब्रह्मचर्यमेव तद्यद्रात्रौ रत्या संयुज्यन्ते ॥९॥

The month is considered to be the lord Prajāpati. Its dark fortnight represents 'rayi', i.e. wealth. The bright fortnight symbolizes 'Prāṇa', i.e. life, and therefore, sages perform bright sacrifices during this time. Day and night are also seen as the lord Prajāpati, with day representing life and night representing wealth. Those who engage in activities during the day are said to leap towards life, while celibacy is associated with those who leap forward at night.

Bhāṣya 01.09

In the couple, divine Vishnu resides in the wife as Saraswati, and in the husband as Vayu. By understanding this, one attains liberation.

"मासस्थितः स भगवान् पक्षयोर्वाक्च मारुतः। अहोरात्रे तु भगवान् प्राणो ह्यहनि वाङ्निशि॥

"The Lord is situated in the month, representing speech and wind during the fortnights, respectively. The day and night are that Lord, embodying life air during the day and speech at night.

दम्पत्योर्भगवान् विष्णुः भार्यास्था तु सरस्वती। भर्तृस्थः स स्वयं वायुः एवं जानन् विमुच्यते॥"

In the couple, divine Vishnu resides in the wife as Saraswati, and in the husband as Vayu. Understanding this, one attains liberation."

इति प्रजापतिसंहितायाम्।

- stated thus in the collection of Prajapati Vedic hymns.