Bukhari

Hadith Commentary: The meaning of the statement of Umar radi Allahu anhu is that although Ubayy bin Ka'b radi Allahu anhu is the most proficient reciter of the Qur'an among us, there are some verses that he recites whose recitation has been abrogated, because the news of abrogation did not reach him.

From this statement of Umar radi Allahu anhu, it is clearly proven that no matter how great a scholar someone may be, not all of his statements are worthy of acceptance.

Error and slip are possible from every scholar.

Whether great or small, only the Prophets and Messengers of Allah are infallible from error (ma'soom 'an al-khata'), for they are honored with direct speech from Allah; no one else shares this status.

The followers (muqallideen) of the four Imams should take a lesson from this.

The rigidity in following them has given the four schools of thought (madhahib arba‘a) the status of four separate religions.

Every Hanafi looks at a Shafi'i with disdain, and every Shafi'i, upon seeing a Hanafi, becomes agitated—except those whom Allah wills.

How regrettable this is.

Imam Abu Hanifah and Imam Shafi'i rahimahullah never held the view that their names should be used to give a juristic school (fiqhi madhhab) the status of an independent religion, thereby fragmenting the Ummah.

It has been rightly said: "They made four religions out of the true religion, and thus created a breach in the religion of the Prophet."

The final statement of every great Imam is this: The real religion is the Qur'an and Hadith; whatever of their statements conforms to the Qur'an should be accepted wholeheartedly, and whatever opposes the Qur'an and Hadith should be abandoned. And this belief should be held that the possibility of error exists for everyone; only the Prophets and Messengers are infallible from error (ma'soom 'an al-khata').

Hadith Commentary:
➊
The meaning of the statement of Umar (radi Allahu anhu) is that although Ubayy ibn Ka'b (radi Allahu anhu) is the most skilled reciter of the Qur'an among us, he still recites some verses whose recitation has been abrogated, but he has not been informed of this abrogation.

➋
With respect to abrogation, there are several types of verses as follows:
© Both the recitation and the ruling have been abrogated.
© Those whose ruling has been abrogated but the recitation remains.
© Those whose recitation has been abrogated but the ruling remains.
© The majority of the Qur'an consists of definitive (muhkam) verses, meaning both their ruling and recitation remain.

➌
From the statement of Umar (radi Allahu anhu), it is also established that no matter how great a scholar may be, not all of his statements are necessarily acceptable; error and slip are possible from every scholar.
Among the servants of Allah, only the noble Prophets (alayhim as-salam) are infallible, as they receive commands directly from Allah, the Exalted.
As for the Imams of the religion and the eminent hadith scholars, even while acknowledging their services, their status is different from that of the Prophets (alayhim as-salam).
Whatever of their statements conforms to the Qur'an and Sunnah is to be accepted wholeheartedly, and whatever contradicts the Qur'an and Sunnah is to be left aside.
This is also the teaching of these esteemed elders.
The possibility of error exists for everyone; only the group of Prophets and Messengers is infallible from error.

➍
The disbelievers and polytheists also objected to the Messenger of Allah (sallallahu alayhi wa sallam), saying that this Prophet is strange: today he commands one action, and tomorrow he forbids it. In response to this objection, the aforementioned verse was revealed, stating that when We abrogate a verse, We send down, according to the needs of the time and the capacity of the people, a better command than the previous one or one similar to it.
It should be noted that according to the research of Shah Waliullah Muhaddith Dehlawi (rahimahullah), only five verses of the Noble Qur'an are abrogated.
And Allah knows best.