These Prophets are the Chosen Ones
Allah says;
أُوْلَيِكَ الَّذِينَ أَنْعَمَ اللَّهُ عَلَيْهِم مِّنَ النَّبِيِّينَ مِن ذُرِّيَّةِ ادَمَ وَمِمَّنْ حَمَلْنَا مَعَ نُوحٍ وَمِن ذُرِّيَّةِ إِبْرَاهِيمَ وَإِسْرَايِيلَ وَمِمَّنْ هَدَيْنَا وَاجْتَبَيْنَا
...
Those were they unto whom Allah bestowed His grace from among the Prophets, of the offspring of Adam, and of those whom We carried (in the ship) with Nuh, and of the offspring of Ibrahim and Israel, and from among those whom We guided and chose.
Allah, the Exalted, says that these Prophets (were favored), but this does not mean only these Prophets who were mentioned in this Surah. Rather, it is referring to all of those who were Prophets. Allah merely changes the implication of the discussion from specific individuals to the entire group of Prophets.
...
الَّذِينَ أَنْعَمَ اللَّهُ عَلَيْهِم مِّنَ النَّبِيِّينَ مِن ذُرِّيَّةِ ادَمَ
...
they unto whom Allah bestowed His grace from among the Prophets, of the offspring of Adam.
As-Suddi and Ibn Jarir both said,
"That which is meant by the offspring of Adam is Idris,
and what is meant by the offspring of those `whom We carried with Nuh' is Ibrahim,
and what is meant by the offspring of Ibrahim is Ishaq, Yaqub and Ismail,
and what is meant by the offspring of Ismail is Musa, Harun, Zakariyya, Yahya and `Isa bin Maryam."
Ibn Jarir said,
"And that is the distinction of their genealogies, even though Adam gathers all of them (as their original father). This is because among them is he who was not a descendant of those who were on the ship with Nuh, and he that is Idris. For verily, he was the grandfather of Nuh."
I say that this is the most apparent meaning, which concludes that Idris is amongst the pillars of Nuh's ancestral lineage. The view that this Ayah refers to the ancestral lineage of the Prophets, is the fact that it is similar to Allah's statement in Surah Al-An`am,
وَتِلْكَ حُجَّتُنَأ ءَاتَيْنَـهَأ إِبْرَهِيمَ عَلَى قَوْمِهِ نَرْفَعُ دَرَجَـتٍ مَّن نَّشَأءُ إِنَّ رَبَّكَ حَكِيمٌ عَلِيمٌ
وَوَهَبْنَا لَهُ إِسْحَـقَ وَيَعْقُوبَ كُلًّ هَدَيْنَا وَنُوحاً هَدَيْنَا مِن قَبْلُ وَمِن ذُرِّيَّتِهِ دَاوُودَ وَسُلَيْمَـنَ وَأَيُّوبَ وَيُوسُفَ وَمُوسَى وَهَـرُونَ وَكَذَلِكَ نَجْزِى الْمُحْسِنِينَ
وَزَكَرِيَّا وَيَحْيَى وَعِيسَى وَإِلْيَاسَ كُلٌّ مِّنَ الصَّـلِحِينَ
وَإِسْمَـعِيلَ وَالْيَسَعَ وَيُونُسَ وَلُوطاً وَكُلًّ فَضَّلْنَا عَلَى الْعَـلَمِينَ
وَمِنْ ءابَايِهِمْ وَذُرِّيَّـتِهِمْ وَإِخْوَنِهِمْ وَاجْتَبَيْنَـهُمْ وَهَدَيْنَـهُمْ إِلَى صِرَطٍ مُّسْتَقِيمٍ
And that was our proof which We gave Ibrahim against his people. We raise whom We will in degrees. Certainly your Lord is All-Wise, All-Knowing.
And We bestowed upon him Ishaq and Yaqub, each of them We guided; and before him We guided Nuh, and among his progeny Dawud, Suleiman, Ayub, Yusuf, Musa and Harun. Thus do We reward the doers of good.
And Zakariyya, and Yahya, and `Isa and Ilyas, each one of them was of the righteous.
And Ismail and Al-Yasa` and Yunus and Lut and each one of them We preferred above the `Alamin.
And also some of their fathers and their progeny and their brethren, We chose them, and We guided them to the straight path. (6:83-87)
Until Allah's statement,
أُوْلَـيِكَ الَّذِينَ هَدَى اللَّهُ فَبِهُدَاهُمُ اقْتَدِهْ
They are those whom Allah had guided. So follow their guidance. (6: 90)
Allah, the Exalted, says,
مِنْهُم مَّن قَصَصْنَا عَلَيْكَ وَمِنْهُمْ مَّن لَّمْ نَقْصُصْ عَلَيْكَ
Of some of them We have related to you their story. And of some We have not related to you their story. (40:78)
In Sahih Al-Bukhari it is reported from Mujahid that he asked Ibn Abbas,
"Is there a prostration in Surah Sad"
Ibn Abbas replied, "Yes."
Then he recited,
أُوْلَـيِكَ الَّذِينَ هَدَى اللَّهُ فَبِهُدَاهُمُ اقْتَدِهْ
They are those whom Allah had guided. So follow their guidance. (6:90)
Ibn Abbas then said, "So your Prophet is one of those who have been commanded to follow them. And he is of those who should be followed." -- referring to Dawud.
Allah, the Exalted, said in this noble Ayah,
...
إِذَا تُتْلَى عَلَيْهِمْ ايَاتُ الرَّحْمَن خَرُّوا سُجَّدًا وَبُكِيًّا
When the Ayah of the Most Gracious were recited unto them, they fell down prostrate and weeping.
This means that when they heard the Words of Allah, mentioning His proofs and evidences, they prostrated to their Lord in humility, humbleness, praise and thanks for the great favors they were blessed with.
The word Bukiyan at the end of the Ayah means those who are crying, and it is the plural of Baki.
Due to this the scholars agree that it is legislated to prostrate upon reading this Ayah, in following them and adhering to their manner of worship.
