Kathina is the one day a year the lay community formally clothes the monastics, held in the month after the rains retreat ends. The economics are the point: monastics own almost nothing and cannot ask, so the entire material basis of the sangha depends on a laity that gives freely — and the ceremony makes that dependence visible and mutual. The monastics give back the only thing they have, which is teaching, and the tradition regards the exchange as the healthiest possible arrangement between a religion and the society carrying it.