Behold, those who are bent on denying the truth and on turning others away from the path of God have indeed gone far astray.
An-Nisa (The Women) Verse 167
The Prophet used to take care of us in preaching by selecting a suitable time, so that we might not get bored. (He abstained from pestering us with sermons and knowledge all the time).
Sahih Bukhari: Volume 1, Book 3, Number 68