SB 12.3.28
yada karmasu kamyesu
bhaktir yasasi dehinam
tada treta rajo-vrttir
iti janihi buddhiman
Translation:
O most intelligent one, when the conditioned souls are devoted to their duties but have ulterior motives and seek personal prestige, you should understand such a situation to be the age of Treta, in which the functions of passion are prominent.