Bayaan : Expounding / Clarification / Declaration.
" This is a declaration for mankind, a guidance and an admonition unto those who ward off (evil)." 3:138
In the above-cited verse, Allaah says about Qur-aan that Qur-aan is the Bayaan (Expounding) for people and that it is a guidance and advice for those who fear Allaah.
We come to know from this verse that Qur-aan is Bayaan - an expounding, a lecture. Whatever lecture we hear that does not relate to Qur-aan is not a deeni - religious lecture. The other thing we come to know is that this lecture, expounding is for people (lin-naas : for the people) and not just for the learned men or any particular class of people.
To those who have the knowledge and understanding of the book and then do not reveal it to the people, for them a grievous punishment has been foretold in the following verses:
" Indeed those who hide the clarifications and the guidance which We revealed, after We had made it clear to mankind in the Scripture: such are accursed of Allaah and accursed of those who curse. " 2:159
" Except those who repent and amend and make manifest (the truth) ; These it is toward whom I relent. I am the Relenting, the Merciful." 2:160
" Indeed those who disbelieve, and die while they are disbelievers; on them is the curse of Allaah and of angels and of men combined." 2:161
" They ever dwell therein. The punishment will not be lightened for them, neither will they be reprieved." 2:162
After the verses which detail the status of those who hide and do not reveal the contents of the book of Allaah and His signs and His guidance, the verse which immediately follows, says:
" Your God is One God; there is no God except Him, the Beneficent, the Merciful." 2:163
From this, the importance of first declaring the One-ness of God among people could be understood.
From another verse, the importance of revealing and expounding the book of Allaah among the people could be understood :
" And (remember) when Allaah laid a charge on those who had received the Scripture (He said): You are to expound it to mankind and not to hide it. But they flung it behind their backs and bought thereby a little gain. Surely evil is that which they have gained thereby." 3:187