a-kāraś cāpy u-kāraś ca ma-kāraś ca tataḥ param
a-kāraś cāpy u-kāraś ca ma-kāraś ca tataḥ param |
veda-trayātmakaṁ proktaṁ praṇavaṁ brahmaṇaḥ padam ||
a-kāreṇocyate viṣṇuḥ śrīr u-kāreṇa cocyate |
ma-kāras tu tayor dāsaḥ pañcaviṁśaḥ prakīrtitaḥ ||
(Padma Purāṇa: 6.227.22-23; cited in Bhakti Sandarbha: 178)
“The letter a along with the letter u and the letter m after that—praṇava [i.e., the word Aum]—is declared to be the basis of the three Vedas and the word for [alt., dwelling place] of Brahman. Viṣṇu is referred to by the letter a, and Śrī is referred to by the letter u. The servant of the two [i.e., of Viṣṇu and Śrī], the twenty-fifth [element in the universe, viz., the jīva], is declared to indeed be the letter m.”