At all events, about five years later his neighbors became much mystified by his behavior. He would retire, for days at a stretch, to a cave in the foothills of Mount Hira, a conical hill several miles north of Mecca, whither Khadija too sometimes went with him. Meanwhile his business languished, and various conjectures were advanced to account for his odd conduct--was the fellow crazy, or afflicted with some loathsome disease, or was he perchance engaged in some such nefarious occupation as counterfeiting? As the months passed, he still continued to act in the same incomprehensible manner, and it was noticed that, little by little, certain members of his immediate family attended him to his refuge, or gathered with him in some one of their own houses. This sort of thing went on for several years, until it was noised abroad that the quondam merchant and camel-driver was confidently claiming the honor of having made the epochal discovery which he phrased thus: “_La ilaha illa Allah, Mohammed rasul Allah_”--which, freely interpreted, means: “There is no god but Allah, and Mohammed is His Prophet.” This brief, twofold credo demands considerable attention. The first postulate was not entirely new, for Allah had hitherto been a well-behaved deity Who was highly regarded by many Arabs; yet, after all, He had been but one of many idols. By what process of thought had Mohammed come to exalt Allah not merely above all Arabian gods, but above the gods of all time? and furthermore, why was he so certain of his own intimate association with Allah? Various explanations were offered by his simple-minded followers. According to one account, as Mohammed was wandering near the cave, “an angel from the sky cried to him, ‘O Mohammed, I am Gabriel!’ He was terrified, for as often as he raised his head, there was the apparition of the angel. He hurried home to tell his wife. ‘O Khadija,’ he said, ‘I have never abhorred anything as I do these idols and soothsayers; and now verily I fear lest I should become a soothsayer myself.’ ‘Never,’ replied his faithful wife, ‘the Lord will never suffer it thus to be.’” So she made haste to get the opinion of her own relative, the aged visionary Waraka, who, after listening attentively to her tale, cried aloud: “By the Lord he speaketh truth! Doubtless it is the beginning of prophecy, and there shall come upon him the _Great Namus_, like as it came upon Moses.” According to another story that is even more edifying, Khadija discreetly tested the genuineness of the angelic guest by making Mohammed sit first on her right knee, and then on her left; and the spirit did not object to either procedure. But when she took Mohammed in her lap and started to remove some of her garments, the virtuous apparition departed in great haste, and the crafty Khadija then exultantly cried: “Rejoice ... for by the Lord! it is an angel, and no devil.”