Brahma Sutras
ॐ असद्व्यपदेशान्नेति चेन्न धर्मान्तरेण वाक्यशेषात् ॐ ॥ २-१-१७॥
If it be argued that the effect did not exist before creation, since it is declared (in the Upanishad) as “non-existent”, then we say, no, because from the complementary portion it is known that the word is used from the standpoint of a difference of characteristics.
english translation
OM asadvyapadezAnneti cenna dharmAntareNa vAkyazeSAt OM ॥ 2-1-17॥
hk transliteration by Sanscript