Malaikah, my question, assuming I understand you correctly above, is that how is Matthew or John writing down Jesus' Sermon on the Mount and other discourses, plus also recording his actions different than the Companions writing down Muhammads recitations and then record Sunnah about him?
Peace,
When Muhammad (sallulahi aleyhi wasalaam) was repeating the quranic revelations from Allah, he would repeat the exact thing that Allah revealed. Even if Allah was addressing him to do/say something...he would repeat it in the same way as it was said to him, thus preserving Allahs words.
eg. Surah Al Ikhlas
1
Say: He is Allah the One and Only
2 Allah the Eternal Absolute
3 He begetteth not nor is He begotten
4 And there is none like unto Him
If he(muhammad) had left out the word "say" then it would have been his own words to the people and not the words of Allah. He simply could have just come and said
He is Allah the One and Only, Allah the Eternal Absolute, He begetteth not nor is He begotten, And there is none like unto Him. but then that would be his own words to the ppl and not Allah's words.
Hence the difference between him saying something from himself based on inspiration (which will be part of the Sunnah and Hadith) and something that came as revelation as part of the Quran.
Now when Jesus did the sermon on the mount, did they record the exact thing he said that God said to him? as shown in the example above? or just what jesus said...... i mean if Jesus spoke the exact thing revealed to him by God (as shown in the example above) or did he speak his message based on what God's inspiration?
That would differentiate whether it is Gods word that was recorded (eg Quran) or a saying of Jesus that was recorded. Remember in islam, even though Quran and Hadith goes together, they are still separated as the word of Allah and the tradition/sayings/practices of Muhammad.