And indeed We have written in Zabur (Psalms) [i.e. all the revealed Holy Books the Taurat (Torah), the Injeel (Gospel), the Quran] after (We have already written in) Al-Lauh Al-Mahfuz (the Book, that is in the heaven with Allah), that My righteous slaves shall inherit the land (i.e. the land of Paradise).
Meaning:-
Al-Lauh Al-Mahfuz: Click Here
Inherit: succeed to, take over, to receive qualities.