SB 10.3.36

TEXT 36
 
TEXT
एवं वां तप्यतोस्तीव्रं तपः परमदुष्करम् ।
दिव्यवर्षसहस्राणि द्वादशेयुर्मदात्मनोः ॥ ३६ ॥
evam vam tapyatos tivram
tapah parama-duskaram
divya-varsa-sahasrani
dvadaseyur mad-atmanoh
evam-in this way; vam-for both of you; tapyatoh-executing austerities; tivram-very severe; tapah-austerity; parama-duskaram-extremely difficult to execute; divya-varsa-celestial years, or years counted according to the higher planetary system; sahasrani-thousand; dvadasa-twelve; iyuh-passed; mat-atmanoh-simply engaged in consciousness of Me.
TRANSLATION
Thus you spent twelve thousand celestial years performing difficult activities of tapasya in consciousness of Me [Krsna consciousness].