Does the follower follow the imam in what he does that contradicts the Sunnah in prayer?

The Shaykh: Does one follow his imam if he prostrates on his knees, or does one contradict his imam and apply this obligatory thing? And we ask for clarification on how to follow the imam?
This is a matter we have spoken about for a long time, and it relates to a principle and to branches that branched off from that principle. The principle is his saying (peace and blessings be upon him): or . This hadith is in "al-Sahihayn" from the narration of a group of the Companions, among them Abu Hurayrah, among them Aishah, and among them Anas ibn Malik, and some of them add to what the others said.
The point is that in this hadith there is the command of the Messenger (peace and blessings be upon him) to the worshippers to follow the imam, and it came at the end of this hadith, as you heard: . This hadith establishes for us this principle, which is the obligation of following the imam; even if he prays sitting down—that is, he is unable to stand—we must follow him in prayer sitting down; that is, we drop the pillar which is standing in order to achieve following the imam and complete emulation of this imam. This is the principle in the subject of the question that came earlier.
As for the matters that confirm this general text: ; for example, in the Sunan from the hadith of al-Mughirah ibn Shu'bah that the Prophet (peace and blessings be upon him and his family) prayed one day, and when he intended to sit for the tashahhud he forgot and stood up for the third rak'ah, so his Companions made tasbih for him, but he did not return for the tashahhud and continued the prayer, then he prostrated the two prostrations of forgetfulness. This same incident happened to the narrator of the hadith, who is al-Mughirah ibn Shu'bah; where he also forgot the first tashahhud in his turn, and that was in the Maghrib prayer, so those behind him made tasbih for him, but he did not turn to them, and at the end of the prayer he prostrated two prostrations and said: "I prayed behind the Prophet (peace and blessings be upon him) and he forgot the tashahhud, so they made tasbih for him, so I did as we did." He said: And he (peace and blessings be upon him) said: . This is the meaning of the hadith of al-Mughirah ibn Shu'bah, so we find here that this hadith obligates the followers who became aware of the imam's error to follow him in his error, even though he left an obligatory duty of the prayer; which is the tashahhud by sitting and reciting.
Indeed, there is in "Sahih al-Bukhari" that the Prophet (peace and blessings be upon him) prayed with his Companions one day the Zuhr prayer five rak'ahs without doing the tashahhud in the fourth rak'ah, and he only did the tashahhud in the fifth rak'ah, and when he said the taslim (peace and blessings be upon him), it was said to him: "O Messenger of Allah, was something added to the prayer?" He said: . They said to him: "But you prayed five," so the Messenger (peace be upon him) prostrated the two prostrations of forgetfulness, then he said: . So we find in this incident that the Companions followed the Messenger (peace and blessings be upon him); even when he stood up for the fifth rak'ah of the Zuhr prayer.
It is said on this occasion that the following of the Companions of the Messenger (peace be upon him) was only because they thought it was possible that a new ruling had come down upon the Messenger (peace be upon him), and that is why he prayed five, and based on this thought, as it was said, they asked him: "Was something added to the prayer?" He answered them in the negative and prostrated two prostrations, and excused himself by saying he was forgetful. This is what some say, that the following of the Companions of the Messenger (peace and blessings be upon him) was only because it occurred to them that it was possible that a new ruling had come; meaning that if they had known with certainty that there was no possibility of adding to the four of Zuhr, they would not have followed him. So we respond to these people from two angles:
The first angle: that this is a mere claim, there is no evidence for what they went to. And the second thing—and it is stronger—is that the Companions and many of the Tabi'un had an incident that was much stranger than this incident, and yet they did not see it permissible for themselves to contradict the imam; for it also came in "Sahih al-Bukhari" that one of the governors in the time of the Umayyads prayed with the people the Fajr prayer four rak'ahs, and he was as if still affected by a drink he had drunk, and after he said the taslim with them he turned to them saying: "Shall I add to you?" As if four is not enough for you instead of two rak'ahs, so I am ready to add; shall I add to you? So we do not find in this incident, despite its anomaly and strangeness and addition, that any of the Companions and Tabi'un said: "This prayer is invalid," and the reason is their consideration of the principle: .
What confirms this to you is what the Imam Abu Dawud narrated in his "Sunan" with his authentic chain that Abdullah ibn Mas'ud (may Allah be pleased with him), when he prayed behind Uthman (may Allah be pleased with him) in Mina, would follow him, and Uthman would pray four rak'ahs while traveling like the other Companions; because that was in the season of Hajj and he was in Mina during the days of Mina, the days of Tashriq, so he would pray with the people in full and not shorten, so Ibn Mas'ud would disapprove of that for him and remind him of what the Messenger (peace be upon him) was doing in the Farewell Pilgrimage and in all his travels, that he would continue to shorten until he returned to Madinah.
The Companions of Ibn Mas'ud would hear from him this disapproval of Uthman, then they would see him on the other hand praying behind him four rak'ahs, so they would say to him: "How is this? You disapprove of him for completing the prayer and then you follow him?" His answer was: "Disagreement is evil." As if Ibn Mas'ud (may Allah be pleased with him) is saying: We are between two evils; the first evil is contradicting the Sunnah in shortening, for the Messenger (peace be upon him) was always and forever shortening, so contradicting this Sunnah is without doubt an evil, but there is another evil; contradicting the imam whom we emulate, this is an evil. And as if he is saying, in what I understand, the Messenger is saying: , and in another hadith he adds and says: , do not contradict him, do as he does. So Ibn Mas'ud says: So we are between two evils, so I choose the lesser of the two evils, and the lesser of them is that I do not contradict the imam. So if I pray with the people as an imam, I would shorten, but if I pray with an imam who does not shorten but completes, then contradicting him is an evil. So this indicates to us that Ibn Mas'ud, and the like of this was also narrated from some of the other Companions like Abu al-Darda and Abu Dharr—I am uncertain now—also prayed behind Uthman in full, and answered with the same answer: "Disagreement is evil."
So from this group of texts, I became convinced that the follower, if he follows an imam and is pleased with him as a model for him, should let his personality disappear behind the personality of this imam, and that his prayer should become the prayer of the imam; whether he hit the mark or erred; because hitting the mark and erring in such matters are matters of ijtihad, and every person naturally claims that the Sunnah is with him; and therefore the Sunnah, from such evidence as the previous, unites the Muslims in their prayer and gathers them behind this one imam, and makes their prayer one with no disagreement among them in it; because disagreement in the same town has a stronger effect than widespread general disagreement. If Allah (Mighty and Majestic) warns generally against disagreement and says: , then disagreement in the same act of worship is more dangerous for those who disagree.
Let no one say—as we have heard repeatedly and over and over—: "How can we leave the Sunnah, for example, we leave placing the hands on the chest, and as came in the question: he prostrates on his knees, we follow him?" Let no one say this; because we do not say: "Follow the imam in what we believe to be an error or a contradiction of the Sunnah for the sake of the imam's feelings," but rather we say this for the sake of the Sunnah itself, if the expression is correct, or rather for the sake of the explicit command of the Messenger (peace be upon him) in his previous saying: , and so on, he says: .
When the imam prays while sitting, he is praying with an excuse. The imam who does not raise his hands in prayer is not raising them with an excuse. The imam who prostrates by placing his hands on his knees is doing so with an excuse, because he believes that this is the Sunnah. Let one of us imagine himself praying behind one of the previous imams, such as the Companions and their like. They were not all in agreement on every issue and every detail. For example, some of the Companions did not perform wudu after touching a woman, while others did perform wudu after touching a woman. There were Companions who did not perform wudu when blood came out, no matter how much it was, and others among them did perform wudu. Did any of them refuse to pray behind one who differed from him in legal opinion? The answer is no. When the imam stands up to lead the people in prayer, personal opinions are erased behind this imam. For example, he touched his wife and did not perform wudu. I hold the view that this touch invalidates wudu. My legal opinion is set aside when I pray behind this imam, and vice versa. The imam raises his hands, but Ibn Mas'ud did not raise his hands. It is well known that Ibn Mas'ud was the basis for the Hanafis in not raising the hands. Did Ibn 'Umar, for example, refuse to follow Ibn Mas'ud and not raise his hands? Meaning, did he refuse to pray behind him? Did he say: "This contradicts the Sunnah"? Or did Ibn Mas'ud, when he prayed behind Ibn 'Umar, say: "This contradicts the Sunnah"? These matters did not separate them at all.
So I say: If the validity or invalidity of the prayer is resolved by the mere act of following, then the one who considers his prayer invalid if he does what the imam does, his prayer becomes valid if he prays behind that imam, because the imam's prayer is valid. So if you pray behind an imam who does not raise his hands and you leave off raising your hands, do you think this is more dangerous than praying behind an imam whose prayer is invalid according to your legal school? For example, I hold the view that eating camel meat invalidates wudu. If I see a man eat camel meat until he belches, and he stands up to pray without performing wudu, do I say: "My prayer is not valid behind him"? No, because following the imam erases all these differences.
Therefore, I return to say: No one of you should ask: "How do we leave the Sunnah for the sake of following the imam?" The answer is: We have left more than the Sunnah. We have left the obligatory, we have left purity, when we pray behind an imam whose prayer is not valid according to our point of view.