Mundaka 6.01
स वेदैतत् परमं ब्रह्मधाम यत्र विश्वं निहितं भाति शुभ्रम्। उपासते पुरुषं ये ह्यकामास्ते शुक्रमेतदति वर्तन्ति धीराः ॥१॥
He knows this supreme abode of Brahman, where the entire universe is placed and shines in its purity. Those wise and courageous ones who worship the Purusha without desires, they transcend and reach the bright one. Lord Vishnu is addressed as 'śukram' i.e. the bright one, substantiated through a testimonial from the Varaha Purana.
Bhāshya 6.01
The chief abode of Lord Viṣṇu is indeed declared as 'prāṇa' i.e. life-force. The Lord is continuously situated in the breath. The wise are always illuminated by the knowledge through the gateway of breath.
स आत्मज्ञार्चको ब्रह्मणो धाम प्राणं वेद। यत्र विश्वं पूर्णं ब्रह्म निहितम्।
'sa' means He, who worships knowledge of Ātmān, who knows the abode of Brahman as the life-force, where the entire universe is situated in Brahman.
"प्रधानं धाम विष्णोस्तु प्राण एव प्रकीर्तितः। उपायैर्यो विजानीयात् प्राणस्थं परमेश्वरम्। तस्य प्राणे हरिर्नित्यमाविष्टो भवति ध्रुवम्॥
"The chief abode of Lord Viṣṇu is indeed declared as 'prāṇa' i.e. life-force. Whoever knows the Supreme Lord situated in the life-force, in his life-force Hari always certainly becomes entered.
नित्यं प्राणस्थितस्यैव विष्णोरावेश एव हि। प्राणद्वारेण यज्ज्ञान दीपनं ज्ञानिनः सदा॥
Indeed, he is continuously situated in the breath, possessed with Lord Vishnu. The wise are always illuminated by the knowledge through the gateway of breath.
सन्निधानं यथा प्राप्ताः पिशाचाः पुरुषेष्वपि। तत्र स्थित्वाऽपि भुञ्जन्त आविशेयुः पुनश्च ते॥
The demons, once they arrive in men, even after staying there and enjoying, would have to enter again.
मन्त्रादिभिस्तथा विष्णुः सदा प्राणस्थितोऽपि सन्। ज्ञानदीप्त्यादिकं कुर्याज्ज्ञानिनः पुनरेव तु॥"
Thus, Lord Viṣṇu, though always present in the life-breath, through mantras and other means, may once again bestow knowledge and illumination upon the wise."
इति च॥
- stated thus, as well.
"एतच्छुक्रं प्रत्यन्यदतिवर्तन्ते। सर्वं तीर्त्वा हरिं शुक्रं प्रतिवृत्तिर्भवेत्पुनः। ज्ञानिनः सा हि मुक्तिः स्यात् तन्नैवात्येति कश्चन॥"
"This bright one surpasses the other. After crossing everything, one returns to the pure essence of Lord Hari. For the wise, this is indeed liberation; no one surpasses this state."
इति महावाराहे।
- stated thus, in the mahāvārāha Purana.