Allah says:

[وَلَقَدْ ضَرَبْنَا لِلنَّاسِ فِى هَـذَا الْقُرْءَانِ مِن كُلِّ مَثَلٍ]

(And indeed We have set forth for mankind, in this Qur'an every kind of parable.) means, `We have explained the truth to them and have made it clear to them, and have set forth for them parables so that they may understand the truth and follow it.'

[وَلَئِن جِئْتَهُمْ بِـَايَةٍ لَّيَقُولَنَّ الَّذِينَ كَفَرُواْ إِنْ أَنتُمْ إِلاَّ مُبْطِلُونَ]

(But if you bring to them any sign or proof, the disbelievers are sure to say (to the believers): "You follow nothing but falsehood and magic.'') If they were to see any kind of sign, whether it was at their own direction or otherwise, they would not believe in it and they would think that it was magic and falsehood, as they said when the moon was cleft asunder, etc., as Allah says:

[إِنَّ الَّذِينَ حَقَّتْ عَلَيْهِمْ كَلِمَةُ رَبِّكَ لاَ يُؤْمِنُونَ - وَلَوْ جَآءَتْهُمْ كُلُّ ءايَةٍ حَتَّى يَرَوُاْ الْعَذَابَ الاٌّلِيمَ ]

(Truly, those, against whom the Word of your Lord has been justified, will not believe. Even if every sign should come to them, until they see the painful torment.) (10:96-97). Allah says here:

[كَذَلِكَ يَطْبَعُ اللَّهُ عَلَى قُلُوبِ الَّذِينَ لاَ يَعْلَمُونَ فَاصْبِرْ إِنَّ وَعْدَ اللَّهِ حَقٌّ]

(Thus does Allah seal up the hearts of those who know not. So be patient. Verily, the promise of Allah is true;) meaning, `bear their stubborn opposition with patience, for Allah will fulfill His promise to grant you victory over them and cause you and those who follow you to prevail in this world and in the Hereafter.'

[وَلاَ يَسْتَخِفَّنَّكَ الَّذِينَ لاَ يُوقِنُونَ]

(and let not those who have no certainty of faith discourage you (from conveying Allah's Message).) `Remain steadfast in the mission with which Allah has sent you, for it is truth in which there is no doubt. Do not turn away from it, for nowhere else is there truth which is to be followed; the truth rests exclusively in the Message with which you have been sent.'