SB 10.3.36
Devanāgarī
एवं वां तप्यतोस्तीव्रं तप: परमदुष्करम् । दिव्यवर्षसहस्राणि द्वादशेयुर्मदात्मनो: ॥ ३६ ॥
Text
evaṁ vāṁ tapyatos tīvraṁ tapaḥ parama-duṣkaram divya-varṣa-sahasrāṇi dvādaśeyur mad-ātmanoḥ
Synonyms
evam—in this way;vām—for both of you;tapyatoḥ—executing austerities;tīvram—very severe;tapaḥ—austerity;parama-duṣkaram—extremely difficult to execute;divya-varṣa—celestial years, or years counted according to the higher planetary system;sahasrāṇi—thousand;dvādaśa—twelve;īyuḥ—passed;mat-ātmanoḥ—simply engaged in consciousness of Me.
Translation
Thus you spent twelve thousand celestial years performing difficult activities of tapasya in consciousness of Me [Kṛṣṇa consciousness].