Chapter 2: Surat Al-Baqarah (The Cow), verses 6-7

Translation:
As for the deniers, whether you warn them or not, they will not have faith. God has set a seal upon their hearts and ears, and on their eyes there is a covering. A grievous punishment awaits them.
Tafsir
(Commentary):
If one
closes one’s eyes, one will not be able to see. If one blocks one’s ears,
one will not be able to hear. However clear the call of truth may be, it can be
understandable and acceptable only if one opens one’s mind to it. God’s
inaudible call in the universe, and the audible expression of that call by the
preacher of God’s word, cannot touch those who have closed minds.
The
call to truth is founded on reality; it accords with nature. When it is raised,
no one can fail to recognize its truth. If one hears it with an open mind, one
will know in one’s heart that it is true. But where society is rigidly bound
by age-old convention, people are less concerned with opening their minds to
divine realities than they are with supporting the vested interests of the
existing regime; with attaining greatness by bowing to the accepted norms of
fame and honour, and with entrenching themselves in key positions—both
religious and secular—as a public expression of personal success. Where the
material outcomes of practical situations are paramount, the preacher of God’s
word is regarded as being out of place.
As
God’s emissary, the preacher is neither a representative nor a supporter of
the conventional set-up. His call, being new and unfamiliar, impinges as a
threat to material security. Much as he urges people to submit to the will of
God, they baulk at doing so, because it would mean demolishing the world they
have made for themselves. It is difficult also for him to convey his message to
highly placed individuals who are afraid that, if they follow an
“insignificant” person, they will thereby suffer some elimination of their
own personal glory. The two greatest obstacles then to the success of the
preacher are worldliness and arrogance. Where the material outcomes of practical
situations are paramount, the preacher of God’s word will be regarded as out
of place.