Belief in the Day of Judgement when all human beings shall be raised from the dead and all their good and bad deeds shall be ultimately judged and recompensed accordingly.
This belief is most essential WITH the belief in the One True God. The Day of Judgement will prove to all in this Universe that the Almighty Allah is the Creator of all from nothing and is the Absolute Master.
His divine presence shall be most apparent on this important Day for all to witness. It is a judgement Day for His creatures to know themselves and their relationship to the Creator Allah. Just as pursuit for justice is inseperable in any society on earth, so is the Ultimate Day of Justice inseparable for mankind.