Śrīmad-Bhāgavatam · Text 10.45.29
Who is speaking and story frame
ततश्च लब्धसंस्कारौ द्विजत्वं प्राप्य सुव्रतौ ।
गर्गाद् यदुकुलाचार्याद्गायत्रं व्रतमास्थितौ ॥ २९ ॥
tataś ca labdha-saṁskārau
dvijatvaṁ prāpya su-vratau
gargād yadu-kulācāryād
gāyatraṁ vratam āsthitau
After attaining twice-born status through initiation, the Lords, sincere in Their vows, took the further vow of celibacy from Garga Muni, the spiritual master of the Yadus.
Read the purport on Vedabase.ioFrom Canto 10, chapter 14 onward, the translation and purports were completed by Śrīla Prabhupāda's disciples after his departure, and published by the Bhaktivedanta Book Trust.