Mahāsalayatana, Mahisalāyatanika Sutta

The Buddha instructs the monks on the necessity of acquiring the right kind of knowledge of the sense organs, their objects, their perception, their contact and the feelings arising there from. Such knowledge enables a monk to traverse the Noble Eightfold Path to its perfected development and to the realization of transcendent knowledge, which is understanding and deliverance. M.iii.287-90.