Śrīmad-Bhāgavatam · Text 2.9.6
Who is speaking and story frame
स चिन्तयन् द्वयक्षरमेकदाम्भ-
स्युपाशृणोद् द्विर्गदितं वचो विभु: ।
स्पर्शेषु यत्षोडशमेकविंशं
निष्किञ्चनानां नृप यद् धनं विदु: ॥ ६ ॥
sa cintayan dvy-akṣaram ekadāmbhasy
upāśṛṇod dvir-gaditaṁ vaco vibhuḥ
sparśeṣu yat ṣoḍaśam ekaviṁśaṁ
niṣkiñcanānāṁ nṛpa yad dhanaṁ viduḥ
While thus engaged in thinking, in the water, Brahmājī heard twice from nearby two syllables joined together. One of the syllables was taken from the sixteenth and the other from the twenty-first of the sparśa alphabets, and both joined to become the wealth of the renounced order of life.
Read Śrīla Prabhupāda's purport on Vedabase.io