The above quote, and many others, from Table Talk (also published as Hitler's Secret Conversations) were recorded by Hitler's secretary Martin Bormann. He would write down what Hitler said on various occasions, thus saving many privately expressed opinions of the Nazi dictator.
As we've recently been debating Hitler's religious views I thought the above was interesting, as is the following from Albert Speer's Inside the Third Reich:
Hitler had been much impressed by a scrap of history he had learned from a delegation of distinguished Arabs. When the Mohammedans attempted to penetrate beyond France into Central Europe during the eight century, his visitors had told him, they had been driven back at the battle of Tours. Had the Arabs won this battle, the world would be Mohammedan today. For theirs was a religion that believed in spreading the faith by the sword and subjugating all nations to that faith. The Germanic peoples would have become the heirs to that religion. Such a creed was perfectly suited to the Germanic temperament. Hitler said that the conquering Arabs, because of their racial inferiority, would in the long run have been unable to contend with the harsher climate and conditions of the country. They could not have kept down the more vigorous natives, so that ultimately not Arabs but Islamized Germans could have stood at the head of this Mohammedan Empire.
Hitler usually concluded this historical speculation by remarking: "You see, it's been our misfortune to have the wrong religion. Why didn't we have the religion of the Japaneses, who regard sacrifice for the Fatherland as the highest good? The Mohammedan religion too would have been much more compatible to use than Christianity with its meekness and flabbiness?"
Hitler the Muslim? Let the debate begin! It is interesting that Hitler says that Islam would have been more "compatible to use", certainly implying that his "Christianity" was just something that he used as well, without any real belief in it at all.