Ibn Mas`ud (May Allah be pleased with him) reported: I heard the Messenger of Allah (PBUH) saying, "May Allah freshen the affairs of a person who hears something from us and communicates it to others exactly as he has heard it (i.e., both the meaning and the words). Many a recepient of knowledge understands it better than the one who has heard it.''
[At-Tirmidhi].

Commentary: Besides mentioning the eminence of knowledge, this Hadith contains inducement for preaching and inviting people towards the path of Allah. It also urges us to communicate knowledge exactly as we have heard it, without changing anything in the least.