One of the great scholars teaching seminary courses in that era was Imam Khomeini.
He was talking on a wide range of topics in connection with Islamic jurisprudence, including the precepts of selling and buying or the principles of commercial trading.
However, he always recommended us to observe our behavior on the way to the acquisition of knowledge and perform useful activities to please God specifically during youth-hood.
Narrated by: Hujjat al-Islam wal Muslimeen Sayyid Ja'far Karimi
Taken from: Pasdar-e Eslam Journal, no. 8