Allah said;

وَإِذَا جَاءتْهُمْ آيَةٌ قَالُواْ لَن نُّؤْمِنَ حَتَّى نُؤْتَى مِثْلَ مَا أُوتِيَ رُسُلُ اللّهِ ...

And when there comes to them a sign they say: "We shall not believe until we receive the like of that which the Messengers of Allah received.''

When there comes to them a sign they say, لَن نُّؤْمِنَ حَتَّى نُؤْتَى مِثْلَ مَا أُوتِيَ رُسُلُ اللّهِ (We shall not believe until we receive the like of that which the Messengers of Allah received.) until the angels bring us the Message from Allah, just as they brought it to the Messengers.

In another Ayah, Allah said,

وَقَالَ الَّذِينَ لاَ يَرْجُونَ لِقَآءَنَا لَوْلاَ أُنزِلَ عَلَيْنَا الْمَلَـئِكَةُ أَوْ نَرَى رَبَّنَا

And those who expect not a meeting with Us said: "Why are not the angels sent down to us, or why do we not see our Lord!" (25:21)

Allah's statement,

... اللّهُ أَعْلَمُ حَيْثُ يَجْعَلُ رِسَالَتَهُ ...

Allah knows best with whom to entrust His Message.

means, He knows best with whom His Message should be given and which of His creatures are suitable for it.

Allah said in other Ayat,

وَقَالُوا لَوْلَا نُزِّلَ هَذَا الْقُرْآنُ عَلَى رَجُلٍ مِّنَ الْقَرْيَتَيْنِ عَظِيمٍ

أَهُمْ يَقْسِمُونَ رَحْمَةَ رَبِّكَ

And they say: "Why is not this Qur'an sent down to some great man of the two towns!" Is it they who would portion out the mercy of your Lord! (43:31-32)

They said, why was not this Qur'an revealed to a mighty, respectable leader, honored by us, مِّنَ الْقَرْيَتَيْنِ (...from one of the two towns) Of Makkah and At-Ta'if. This is because they, may Allah curse them, belittled the Messenger out of envy, transgression, rebellion and defiance. Allah described them,

وَإِذَا رَأَوْكَ إِن يَتَّخِذُونَكَ إِلاَّ هُزُواً أَهَـذَا الَّذِى بَعَثَ اللَّهُ رَسُولاً

And when they see you, they only mock: "Is this the one whom Allah has sent as a Messenger!" (25:41)

and,

وَإِذَا رَآكَ الَّذِينَ كَفَرُواْ إِن يَتَّخِذُونَكَ إِلاَّ هُزُواً أَهَـذَا الَّذِى يَذْكُرُ آلِهَتَكُمْ وَهُمْ بِذِكْرِ الرَّحْمَـنِ هُمْ كَـفِرُونَ

And when those who disbelieved see you, they only mock at you: "Is this the one who talks about your gods!" While they disbelieve at the mention of the Most Gracious (Allah). (21:36)

and,

وَلَقَدِ اسْتُهْزِىءَ بِرُسُلٍ مِّن قَبْلِكَ فَحَاقَ بِالَّذِينَ سَخِرُواْ مِنْهُمْ مَّا كَانُواْ بِهِ يَسْتَهْزِءُونَ

Indeed Messengers were mocked before, but the scoffers were surrounded by that, whereat they used to mock. (21:41)

The Disbelievers Admit to the Prophet's Nobility of Lineage

The disbelievers did all of this although they admitted to the Prophet's virtue, honorable lineage, respectable ancestry and purity of household and upbringing, may Allah, His angels, and the believers send blessings upon him.

The disbelievers used to call the Prophet, before he received revelation, Al-Amin -- the Truthful. The leader of the Quraysh disbelievers, Abu Sufyan, had to admit to this fact when Heraclius, emperor of Rome, asked him, "How honorable is his (the Prophet's) ancestral lineage among you!''

Abu Sufyan answered, "His ancestry is highly regarded among us.''

Heraclius asked, "Do you find that he lied, before he started his mission!''

Abu Sufyan replied, "No.''

The emperor of Rome relied on the honor and purity of the Prophet to recognize the truth of his Prophethood and what he came with.

Imam Ahmad recorded that Wathilah bin Al-Asqa said that the Messenger of Allah said,

إِنَّ اللهَ اصْطَفَى مِنْ وَلَدِ إِبْرَاهِيمَ إِسْمَاعِيلَ، وَاصْطَفَى مِنْ بَنِي إِسْمَاعِيلَ بَنِي كِنَانَةَ وَاصْطَفَى مِنْ بَنِي كِنَانَةَ قُرَيْشًا وَاصْطَفَى مِنْنُقرَيْشٍ بَنِي هَاشِمٍ وَاصْطَفَانِي مِنْ بَنِي هَاشِم

Verily, Allah has chosen Ismail from the offspring of Ibrahim, Bani Kinanah from the offspring of Ismail, Quraysh from Bani Kinanah, Bani Hashim from Quraysh and, He has chosen me from Bani Hashim.

Muslim recorded this Hadith.

Al-Bukhari recorded that Abu Hurayrah said that the Messenger of Allah said,

بُعِثْتُ مِنْ خَيْرِ قُرُونِ بَنِي آدَمَ قَرْنًا فَقَرْنًا، حَتَّى بُعِثْتُ مِنَ الْقَرْنِ الَّذِي كُنْتُ فِيه

I was chosen from a succession of the best generations of the Children of Adam, until the generation I was sent in.

Allah's said,

... سَيُصِيبُ الَّذِينَ أَجْرَمُواْ صَغَارٌ عِندَ اللّهِ وَعَذَابٌ شَدِيدٌ ...

Humiliation and disgrace from Allah and a severe torment will overtake the criminals...,

This is a stern threat and sure promise from Allah for those who arrogantly refrain from obeying His Messengers and adhering to what they came with. On the Day of Resurrection, they will suffer humiliation and eternal disgrace before Allah, because they were arrogant in the worldly life. This is why it is befitting that they earn disgrace on the Day of Resurrection.

Allah said in another Ayah,

إِنَّ الَّذِينَ يَسْتَكْبِرُونَ عَنْ عِبَادَتِى سَيَدْخُلُونَ جَهَنَّمَ دَخِرِينَ

Verily, those who scorn My worship, they will surely enter Hell in humiliation! (40:60),

disgrace and dishonor.

Allah said next,

... وَعَذَابٌ شَدِيدٌ بِمَا كَانُواْ يَمْكُرُونَ ﴿١٢٤﴾

and a severe torment for that which they used to plot.

Since plotting usually takes place in secret and involves treachery and deceit, the disbelievers were recompensed with severe torment from Allah on the Day of Resurrection, as a just reckoning,

وَلاَ يَظْلِمُ رَبُّكَ أَحَدًا

And your Lord treats no one with injustice. (18:49)

Allah said in another Ayah,

يَوْمَ تُبْلَى السَّرَآئِرُ

The Day when all the secrets will be examined. (86:9)

Meaning, the secrets, hidden thoughts and intentions will be exposed.

In the Two Sahihs, it is recorded that the Messenger of Allah said,

يُنْصَبُ لِكُلِّ غَادِرٍ لِوَاءٌ عِنْدَ اسْتِهِ يَوْمَ الْقِيَامَةِ، فَيُقَالُ: هَذِهِ غَدْرَةُ فُلَانِ بْنِ فُلَانِ بْنِ فُلَان

A banner will be raised for every deceitful person from his anus on the Day of Resurrection, and it will say; `This is the treacherous plot of so-and-so, son of so-and-so, son of so-and-so.

The wisdom in this is that since a plot occurs in secret, and people are usually unaware of it, then on the Day of Resurrection the plot itself will become public news testifying to the actions of those who committed it.