CC Ādi 15.22
ki kāraṇe līlā, — ihā bujhite nā pāri
In this way Lord Caitanya Mahāprabhu performed various pastimes, but why He did so I cannot understand.
The Supreme Personality of Godhead and His devotees who come to this world are executing a mission, and therefore sometimes they act in a way that is very difficult to understand. It is said, therefore, vaiṣṇavera kriyā-mudrā vijñeha nā bujhaya: even if one is a very learned and intelligent scholar, he cannot understand the activities of a Vaiṣṇava. A Vaiṣṇava accepts anything favorable for executing his mission. But foolish persons, not knowing the purpose of such exalted Vaiṣṇavas, indulge in criticizing them. That is forbidden. Since no one can understand what a Vaiṣṇava does for the purpose of executing his mission, to criticize such a Vaiṣṇava is the offense called sādhu-nindā.