Surat Ar-Rūm (The Romans) - سورة الروم

: And those who have been bestowed with knowledge and faith will say: "Indeed you have stayed according to the Decree of Allah, until the Day of Resurrection, so this is the Day of Resurrection, but you knew not."

: So on that Day no excuse of theirs will avail those who did wrong (by associating partners in worship with Allah, and by denying the Day of Resurrection), nor will they be allowed (then) to return to seek Allah's Pleasure (by having Islamic Faith with righteous deeds and by giving up polytheism, sins and crimes with repentance).

: And indeed We have set forth for mankind, in this Quran every kind of parable. But if you (O Muhammad SAW) bring to them any sign or proof, (as an evidence for the truth of your Prophethood), the disbelievers are sure to say (to the believers): "You follow nothing but falsehood, and magic."

: Thus does Allah seal up the hearts of those who know not [the proofs and evidence of the Oneness of Allah i.e. those who try not to understand true facts that which you (Muhammad SAW) have brought to them].

: So be patient (O Muhammad SAW). Verily, the Promise of Allah is true, and let not those who have no certainty of faith, discourage you from conveying Allah's Message (which you are obliged to convey)