少壮不努力，老大徒伤悲 shàozhuàngbùnǔlìlǎodàtúshāngbēi if you are lazy in your youth, you will regret it in your old age
A proverb meaning that if one does not work hard while young and strong, one will only have useless regrets when old; from the Han dynasty poem [[长歌行|長歌行|chang2 ge1 xing2]]