Nibbedhikapaññā sutta: Penetrating Wisdom

“Mendicants, when four things are developed and cultivated they lead to penetrating wisdom. What four? Associating with true persons, listening to the true teaching, rational application of mind, and practicing in line with the teaching. When these four things are developed and cultivated they lead to penetrating wisdom.”

The Linked Discourses on Stream-Entry, the eleventh section.