Behold, as for those who are bent on denying the truth and die as deniers of the truth -their due is rejection by God, and by the angels,, and by all [righteous] men.
Al-Baqara (The Cow) Verse 161
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