The change by Ibn Mas'ud (may Allah be pleased with him) of the wording of the tashahhud was merely a hint from the Prophet (peace and blessings be upon him) to Ibn Mas'ud.

The questioner : ... .

The Shaykh : The issue is... the first issue; let us pause here for a moment. If it had been Ibn Mas'ud (may Allah be pleased with him) alone, I would have found it unlikely to be an issue; because he was, first of all, a jurist among the great jurists of the Companions, and in addition to that, he was an enemy of innovators and of religious innovation. It is rare to find his like among the known Companions who were also distinguished by jurisprudence and knowledge. Among his sayings is: "Economy in the Sunnah is better than ijtihad in religious innovation." Economy in the Sunnah means that you practice the Sunnah, even if it is little, and that is better and more excellent than ijtihad in religious innovation. And among his sayings is: "Follow and do not innovate; you have been sufficed. Hold fast to the ancient way." "Hold fast to the ancient way" means what the Messenger (may the prayers and peace of Allah be upon him) was upon. And from that is his saying (may Allah be pleased with him) when Abu Musa al-Ash'ari came to him one morning, as he was leaving his home heading with him to the mosque for the Fajr prayer. Abu Musa said: "O Abu 'Abd al-Rahman" — the kunya of 'Abd Allah ibn Mas'ud is Abu 'Abd al-Rahman — "O Abu 'Abd al-Rahman, I just now saw something in the mosque that I disapproved of, and yet, praise be to Allah, I saw nothing but good." He said: "What did you see?" He said: "If you live, you will see it. I just now saw in the mosque people in circles, and in the middle of each circle was a man saying to them: 'Say Subhan Allah so much, Alhamdulillah so much, Allahu Akbar so much,' and with each of them were pebbles with which he counted the tasbih, takbir, and tahmid." Ibn Mas'ud said: "Did you not disapprove of them? Did you not order them to count their sins, and did you not guarantee for them that nothing of their good deeds would be lost?" He said: "No, I was waiting for your order — or waiting for your opinion."
Here I must pause so that we may take a lesson from this... and perhaps our brothers, the students of knowledge, may benefit from it. Abu Musa al-Ash'ari says to Ibn Mas'ud: "I did not disapprove of them, even though they were a matter for disapproval, because I do not precede you in disapproval; for you are more knowledgeable than I. I was waiting for your order — or waiting for your opinion." Today, in many gatherings where there is a scholar, or even a strong student of knowledge, a question is directed to him, and you find someone other than the one addressed rushing to answer. This is a lack of proper conduct on the part of students of knowledge. First, some of them must know the standing of others, and second, and more importantly, they must know the etiquettes of gatherings with scholars and people of virtue. Therefore, it is not permissible for them to precede them in answering a question directed to them. This is why Abu Musa said — and he had seen something he disapproved of, and Ibn Mas'ud was not present with him, not with him, but he kept in his mind and in his thoughts that there was someone near us who was more knowledgeable than us. And so he was content to convey the picture of what he disapproved of to the one who was more knowledgeable than him. When Ibn Mas'ud said to him: "Did you not disapprove of them? Did you not order them to count some of their sins?" — he said: "No, it is not for me to precede in disapproval while you are present. No, I will not do that, I am waiting for your order — or waiting for your opinion." This is an admonition that I hope you will remember, and that you will adopt this great Companion's etiquette.
The completion of the story is that when Ibn Mas'ud heard from Abu Musa what he heard, he returned to his house, then he went out veiled so that he would not be recognized, and he proceeded to the mosque until he stood by the circles that had been described to him. After that, he uncovered his face and said: "Woe to you! What is this that you are doing? I am 'Abd Allah ibn Mas'ud, a Companion of the Messenger of Allah (peace and blessings be upon him)." They said: "By Allah, O Abu 'Abd al-Rahman — meaning it is a simple, easy matter — we are counting the tasbih, takbir, and tahmid with pebbles." He said: "Count your sins, and I am the guarantor for you that nothing of your good deeds will be lost for you with Allah (Blessed and Exalted is He). Count your sins, and I am the guarantor for you that nothing of your good deeds will be lost for you with Allah. Woe to you! How quickly you are perishing! These are his garments (peace and blessings be upon him) and they have not worn out, and these are his vessels and they have not been broken. By Him in whose hand is my soul, are you more guided than the Ummah of Muhammad, or are you holding fast to a rope of misguidance?" Of course... it is impossible. "Are you more guided than the Ummah of Muhammad" is impossible; so only the other remains: "or are you holding fast to a rope of misguidance." They said: "O Abu 'Abd al-Rahman, we only intended good!" He said: "And how many are those who intend good but do not attain it!" A profound wisdom; "And how many are those who intend good but do not attain it. Muhammad (peace and blessings be upon him) told us: ." The witness of this story said: "And we certainly saw those people — the people of the circles — fighting us on the day of al-Nahrawan"; meaning: they became among the Khawarij who rebelled against the Rightly Guided Caliph 'Ali ibn Abi Talib, and he fought them until he uprooted their roots, so that only a few individuals escaped from them, who were the origin of the Khawarij thereafter.
The point is that Ibn Mas'ud (may Allah be pleased with him) was, first of all, among the scholars and great jurists of the Companions, and then he had a keenness of insight in disapproving of religious innovations, and you have heard what he said about some of them just now. So how can we imagine that he would come to the saying of the Prophet (peace and blessings be upon him) when he taught him the tashahhud and his hand was between the hands of the Messenger (peace and blessings be upon him)? It was among what he said: to the end of it. It is impossible for such a noble Companion to raise the basis of the address in and change the phrase to the third person, saying: on his own, while he takes his companions to task for a single letter. With this and that, it is impossible. How, when he did not say: "When the Prophet died, I said: Peace be upon the Prophet," but rather he said: "When the Prophet died, we said: "? So this is not ijtihad from him or an action from him such that it can be said that he erred. It is never easy to attribute error to such a Companion, and in this specific point, because it relates to a principle he had in fighting the changing of adhkar and awrad and adding to them. How... regarding the others - also - of the Companions of the Messenger (peace be upon him), he said: "When he died, we said: ." Then came what supports this explanation; we said: Peace be upon the Prophet. 'Abd al-Razzaq narrated in his Musannaf with his authentic chain from Tawus that the Prophet (peace and blessings be upon him) — Tawus, I am unsure now, Tawus or 'Ata, and in any case both are trustworthy — "that the Companions of the Prophet (peace and blessings be upon him) used to say — while the Prophet (peace and blessings be upon him) was alive —: , and when he died they said: ."
So it should not occur to anyone's mind that Ibn Mas'ud changed this address on his own. Rather, it is even more fitting that it should not occur to anyone's mind that the Companions agreed to change this address from the second person to the third person. Rather, that was by the instruction of the Messenger (peace and blessings be upon him) to them; meaning: the Prophet (may Allah's prayers and peace be upon him) had hinted to them that this teaching was for his lifetime, whereas after his death it would be: . Therefore, following many of the Shafi'i imams, we say in our tashahhud: .
As for the Prophet (peace and blessings be upon him), he hears the voice when he is greeted, and this is what we say in the tashahhud. So this is a statement we say in the tashahhud: , and it is not good in reason to address one who does not hear. So the Messenger of Allah hears! This restriction and this modification, which is by the instruction of the Messenger, is because today it is not permissible for us to say: , but rather you say: .
This is what I have, and perhaps this amount is sufficient...