All religions have some truth in them, but none has the whole truth; all are created in time and finally decline and perish. Mahomed himself never pretended that the Koran was the last message of God and there would be no other. God and Truth outlast these religions and manifest themselves anew in whatever way or form the Divine Wisdom chooses.
When death brings at last the desired forgetfulness, it abolishes life and being together, and sets the seal on the knowledge that "being" is merely a continual "has been," a thing that lives by denying and destroying and contradicting itself.