In his "Chapter concerning making clear when the one who rules by other than what Allaah revealed is a Kaafir; with the Kufr that does not take one outside the Milla."

Then he said, "He does not disbelieve with three conditions:
a) That he is Multazim (i. e. religiously committed) and accepts upon the outside and the inside every Hukm or Tashree' (legislation) which has come from Allaah subhaanahuu wa-ta'ala or His Messenger -sallallaahu 'alayhi wa sallam.
b) That he accepts and confesses that he has left the Hukm with what Allaah subhaanahuu wa-ta'ala has revealed in that matter or that specific instance that he judges in that he is sinful and that his Hukm is a mistake and that the Hukm of Allaah is the correct.
c) That the opposing Hukm is a Hukm in specific instances and not in full general matters and this third condition is the one, which many of the contemporary people have not understood and paid attention to.
– "In'Allaah Huu'al-Haakim", Pg. 88-91 published by "Daar Al-Waton", 1413 H.