B.G 9.19
tapāmyahamahaṁ varṣaṁ nigr̥hṇāmyutsr̥jāmi ca। amr̥taṁ caiva mr̥tyuśca sadasaccāhamarjuna ॥19॥
I am the source of heat, and I withhold and send forth the rain. O Arjuna, know that I encompass both immortality and death, and I am simultaneously the cause and effect.
Gīta Bhāshya 9.19
In the current context 'Sat' means the effect, and 'Asat' is used to mean the cause. Same is substantiated through testimonials.
"sat kāryam। asat kāranam। sadabhivyaktarupatvāt kāraṇaṁ cāpi śabditam॥"
"'Sat' is the effect; 'Asat' is the cause. Because the manifest is of the nature of expression, the cause too is denoted by the term."
iti hyabhidhānam।
- Thus indeed is the declaration.
"asacca saccaiva yadviśvaṁ sadasataḥ param॥"
"That which is the universe, composed of both the unmanifest and manifest, is beyond both cause and effect."
iti ca bhārate ॥19॥
- stated thus in the Mahābhārata as well.
Gīta Tātparya 9.19
Due to the completeness of virtuous qualities, supreme Lord Vishnu is called 'sat'. As no one else is superior in qualities to Lord Vishnu, i.e. He is beyond ordinary qualities. Hence he is spoken of as 'asat'.
"sat sādhuguṇapūrṇatvādasmānnānyo guṇādhikaḥ। yato'to'saditiproktaṁ viṣṇvākhyaṁ paramaṁ padam॥"
"Due to the completeness of virtuous qualities, supreme Lord Vishnu is called 'sat'; no one else is superior in qualities to Lord Vishnu, i.e. He is beyond ordinary qualities, hence he is spoken as 'asat'."
iti śabdanirṇaye ॥16-19॥
- stated thus in the śabdanirṇaya, a book on the determination of words.
