Ramayana
एवं वर्षसहस्राणि दश तेषां ययुस्तदा । धर्मे प्रयतमानानां पौरकार्येषु नित्यदा ॥ 7-102-16 ॥
In this way ten thousand years passed for them as they strove ever in righteousness and were constantly engaged in the affairs of the citizens.
english translation