It is reported in some narratives that there were three scribes who would deliberately alter the revelation dictated to them by the Prophet (sws). The most prominent among them is 'Abdullāh ibn Sa'd ibn Abī Sarah. Al-Wāqidī (d. 207 AH) records:
قَالُوا: وَكَانَ عَبْدُ اللّهِ بْنُ سَعْدِ بْنِ أَبِى سَرْحٍ يَكْتُبُ لِرَسُولِ اللّهِ الْوَحْىَ فَرُبّمَا أَمْلَى عَلَيْهِ رَسُولُ اللّهِ سَمِيعٌ عَلِيمٌ فَيُكْتَبُ عَلِيمٌ حَكِيمٌ، فَيَقْرَأُ رَسُولُ اللّهِ فَيَقُولُ: كَذَلِكَ اللّهُ وَيُقِرّهُ، وَافْتُتِنَ، وَقَالَ: مَا يَدْرِى مُحَمّدٌ مَا يَقُولُ إنّى لأَكْتُبُ لَهُ مَا شِئْت، هَذَا الّذِى كَتَبْت يُوحَى إلَىّ كَمَا يُوحَى إلَى مُحَمّدٍ، وَخَرَجَ هَارِبًا مِنْ الْمَدِينَةِ إلَى مَكّةَ مُرْتَدّا، فَأَهْدَرَ رَسُولُ اللّهِ دَمَهُ يَوْمَ الْفَتْحِ
They said: " 'Abdullāh ibn Sa'd ibn Abī Sarah would write the revelation for the Prophet. So sometimes when the Prophet (sws) would ask him to write سَمِيعٌ عَلِيمٌم (God hears and knows everything), he would write عَليِمٌ حَكِيم (God knows everything and is wise). The Prophet (sws) would then recite to him and say: 'God has revealed it thus,' and he would leave the revelation intact. And this led Ibn Abī Sarah to a trial and he said: 'Muhammad does not know what he says; I write for him whatever I want; This what I write has been revealed to me just as it was revealed to Muhammad.' He then ran away from Madīnah to Makkah recanting Islam. The Messenger of God forgave his life on the day Makkah was conquered."
Al-Ansārī records on the authority of Hishām ibn al-Kalbī (d. 204 AH):
وقال ابن الكلبي حبيب بن جذيمة بالتخفيفأسلم قبل الفتح وهاجر وكان يكتب الوحيقال غيره وهو أول من كتب لرسول الله صلى الله عليه وسلم من قريشقال ثم ارتد ورجع إلى مكة وقالإني كنت أصرف محمدا حيث أريد كان يملي علي عَزِيْزٌ حَكِيْمٌ فأقول أو عَلِيْمٌ حَكِيْمٌ فيقول (كل صواب)
Ibn al-Kalbi said: "Habīb ibn Jazīmah ['Abdullah ibn Sa'd ibn Abī Sarah] embraced faith before the conquest of Makkah and migrated [to Madīnah]. And he would write divine revelation [or as per another view] he was the first to write for the Prophet (sws) from the Quraysh. He then recanted Islam and returned to Makkah and said: 'I would change [the dictation of Muhammad (sws)] to what I wanted. He would dictate: "عَزِيْزٌ حَكِيْمٌ." I would say: "or عَلِيْمٌ حَكِيْمٌ." At this, he replied: "Both are correct."'" 
Muhammad Mustafā A'zamī (b. 1931), a contemporary Islamic scholar, has critically evaluated these narratives. Presented below is a summary of his criticism.
1. Foremost sources like Ibn Hishām (218 AH), Ibn Sa'd (d. 230 AH), Khalīfah ibn Khayyāt(d. 240 AH)and al-Tabarī (d. 310 AH) do not mention this tampering of Ibn Abī Sarah. All they mention is that he was a scribe who later recanted Islam.
It may also be added to this point of criticism made by A'zamī that Abū Dā'ūd (d. 275 AH) and al-Nasā'ī (d. 303 AH) are also devoid of any mention of this tampering and only mention his apostasy. Furthermore, narratives which mention that 'Abdullāh ibn Sa'd ibn Abī Sarah tampered with Qur'ānic verses while writing them down do not have a complete chain of narration.
2. The Prophet (sws) would always have the person read out to him the revelation he had written. So how can a wrongly written verse still be found.
3. How can it be believed that the Prophet (sws) would corroborate what the person had written when actually what had been revealed to him was something else?
4. If is it supposed that such an incident happened once, how can it be assumed that the Prophet (sws) would have persisted with him as a scribe once his mischief came to his notice?
5. Al-Wāqidī and Ibn Kalbī are untrustworthy narrators.
6. The same incident has been attributed to other persons besides him: among them are 'Abdullāh ibn Khatal and a Christian who had recanted Islam.
While referring to 'Abdullāh ibn Khatal, Ibn Sayyid al-Nās records:
وروينا من طريق النزال بن سبرة عن علي قال كان ابنخطل يكتب قدام النبي صلّى الله عليه وسلّم فكان إذا نزل « غفور رحيم » كتب رحيم غفور وإذا نزل « سميع عليم » كتب عليم سميع. وفيه فقال ابن خطل ما كنت أكتب إلا ما أريد ثم كفر ولحق بمكة
'Alī said: "Ibn Khatal would write in front of the Prophet. So when غفور رحيم would be revealed, he would write: رحيم غفور, and when سميع عليم would be revealed, he would write: عليم سميع." And in the same narrative Ibn Khatal said: "I would only write what I wanted." Then he became a disbeliever and ran away to Makkah.
However, after mentioning his name, Ibn Sayyid al-Nās writes that the narrative has been misreported and that the person in question was actually 'Abdullāh ibn Sa'd ibn Abī Sarah.
A'zamī has referred to some more details about him in line with the view expressed by Ibn Sayyid al-Nās. He finally concludes on the basis of Ibn Ishāq that Ibn Khatal was never a scribe; he was made a tax-collector by the Prophet (sws) and was guilty of killing his innocent servant and he later recanted Islam.