Prabhupada said that to strengthen our intelligence means that before we do anything, we compare it to the instructions we received from guru and Krishna. And by building everything that we do on those higher instructions, our intelligence becomes stronger. Prabhupada even said that for the disciple, intelligence means… the instructions of the spiritual master. Therefore before we do anything we should be thinking, "Is this what I should be doing?" And compare it.
Conversation with a disciple, 2017-11-27