What is al-lawh al-mahfooz?

Could you explain in detail including tafseer of the great scholars of Islam (Ibn Katheer ,At-Tabari etc.)the notion "allauh al mahfuz" mentioned in the Holy Qur'aan (85:22)?
Jazakallahu khairan !

Praise be to Allaah.

1. Ibn Manzoor said:

Al-Lawh: every wide, flat surface or sheet of wood.

Al-Azhari said: al-Lawh is a flat surface of wood, and a shoulder-blade [of an animal], if it is written on, may be called a lawh.

Al-Lawh is something that is written on.

Al-Lawh: al-Lawh al-Mahfooz, as in the aayah (interpretation of the meaning), “(Inscribed) in al-Lawh al-Mahfooz (the Preserved Tablet)” [al-Burooj 85:22] means, the place where the decrees of Allaah are kept.

Every wide bone is a lawh.

The plural form is alwaah….

(Lisaan al-‘Arab, 2/584).

2. Ibn Katheer (may Allaah have mercy on him) said:

“in al-Lawh al-Mahfooz (the Preserved Tablet)” means, It is among the higher group (i.e., angels), preserved and protected from anything being added or taken away, or any alteration or changes.

(Tafseer Ibn Katheer, 4/497, 498).

3. Ibn al-Qayyim (may Allaah have mercy on him) said:

“Preserved”: most readers recite this with a kasrah, i.e., it is a description of the Lawh. This indicates that the shayaateen are not able to bring it down, because its location is protected and they cannot reach it. And it is itself protected, so the Shaytaan cannot add anything to it or take anything away from it.

Allaah, may He be glorified, has described it as protected or guarded in the aayah (interpretation of the meaning):

“Verily, We, it is We Who have sent down the Dhikr (i.e. the Qur’aan) and surely, We will guard it (from corruption).” [al-Hijr 15:9]. And its location is also described as being guarded in this soorah.

Allaah, may He be glorified, is protecting its location, and protecting it from having anything added or taken away, or being distorted. He is protecting its meanings from being twisted, just as He is protecting its words from being changed, and He is protecting its letters so that nothing is added or taken away…

(al-Tabyaan fi Aqsaam al-Qur’aan, p. 62).

4. As for the reports in some books of Tafseer, that al-Lawh al-mahfooz is on the forehead of Israafeel or that is was created of green chrysolite, etc., none of these reports have been proven. It is part of the Unseen (al-ghayb) of which we cannot accept any reports except from the one who received Revelation concerning it.

And Allaah knows best.