The effects produced by his preaching, and the changes wrought by them in the religious, social, and political sphere of the polytheists, the idolatrous and grossly superstitious Arabs within a comparatively short period, mostly consisting of persecutions at Mecca, and struggles at Medina, were very striking. From an indiscriminate mass of polytheism and gross superstitious belief in gods, genii, the sons and daughters of God, he gave them a pure monotheistic belief, recognizing no other superior power but the Almighty. He raised the moral standard of his countrymen, ameliorated the condition of women, curtailed and mitigated polygamy and slavery, and virtually abolished them as well as infanticide. He most sternly denounced and absolutely forbade many heinous evils of the Arab society. He united a number of wild and independent tribes into a nation and abolished their internecine wars. Sir W. Muir says:-- "Few and simple as the positive precepts of Mahomet up to this time appear, they had wrought a marvellous and a mighty work. Never, since the days when primitive Christianity startled the world from its sleep, and waged a mortal combat with Heathenism, had men seen the like arousing of spiritual life, the like faith that suffered sacrifice and took joyfully the spoiling of goods for conscience sake. "From time beyond memory, Mecca and the whole Peninsula had been steeped into spiritual torpor. The slight and transient influence of Judaism, Christianity, or Philosophy upon the Arab mind, had been but as the ruffling here and there the surface of a quiet lake;--all remained still and motionless below. The people were sunk in superstition, cruelty, and vice. It was a common practice for the eldest son to marry his father's widows inherited as property with the rest of the estate. Pride and poverty had introduced among them, as it has among the Hindus, the crime of female infanticide. Their religion consisted in gross idolatry, and their faith was rather the dark superstitious dread of unseen beings, whose goodwill they sought to propitiate, and to avert their displeasure, than the belief in an over-ruling Providence. The Life to come and Retribution of good and evil were, as motives of action, practically unknown.