لَّا يَمَسُّهُ إِلَّا الْمُطَهَّرُونَ
“None touch it except the purified”.
This ayah speaks of a touch tied to the Kitaab Maknoon, understood here as Al-Lawh ul-Mahfoozh, and the purified are the special angels who alone have access to it.
الْمُطَهَّرُونَ
Al-Mutah’haroona
This word traces to الطُّهْر (At-Tuhr), a term used for purity and for the opposite of menses and impurity.
It is said:
طَهُرَتِ المَرْأَة
meaning that the blood from a woman’s menses has stopped.
This root is used for both physical purity and non-physical purity in relation to what is filthy, harmful, foul, and impure.
The Kitaab Maknoon is Al-Lawh ul-Mahfoozh, the preserved tablet.
This is further illuminated by Surah ‘Abasa, with its mention of the honoured, exalted, purified sheets carried by noble messenger-angels:
كَلَّا إِنَّهَا تَذْكِرَةٌ ﴿١١﴾ فَمَنْ شَاءَ ذَكَرَهُ ﴿١٢﴾ فِي صُحُفٍ مُّكَرَّمَةٍ ﴿١٣﴾ مَّرْفُوعَةٍ مُّطَهَّرَةٍ ﴿١٤﴾ بِأَيْدِي سَفَرَةٍ ﴿١٥﴾ كِرَامٍ بَرَرَةٍ
“No! Indeed, it is a reminder; (11) So whoever wills may remember it. (12) [It is recorded] in honoured sheets, (13) Exalted and purified, (14) [Carried] by the hands of messenger-angels, (15) Noble and dutiful” (11–16).
Only these special angels have access to this concealed book or preserved tablet.
The source is the concealed book, understood as Al-Lawh ul-Mahfoozh.
The purified are the special angels who alone may access it.
Jibreel (as) then takes it from there and delivers it to the Messenger of Allah ﷺ.
Here, الْمُطَهَّرُونَ refers to the angels who have access to the concealed book and none but them can touch it.
This indicates that the revelation cannot be tampered with, corrupted, or changed by any impure sources on its way to the Messenger ﷺ.