Among moral teachings: self-restraint, forgiveness and tolerance are sternest one for a human being to adopt, Islam has conquered this hard tract of human nature very easily.
Islam lays great stress on tolerance, self-restraint forbearance and forgiveness. It exhorts Muslims to adopt these high moral qualities. Holy-Qur’an and the prophets Hadiths are full of injunctions which excite them to forgive and forbear.
The Holy-Qur’an says,
"Who restrain anger and pardon (all) men for Allah loves those who do good." (Aal-e-Imran 134)
It further says,
"Let them forgive and overlook, do you not wish that Allah should forgive you? For Allah is oft-Forgiving, Most Merciful".
Islam is based on Monotheism. Besides having deep faith in the presence of one Allah (God) it tries its best to set His greatness and glory in the hearts of people. Yet it exhorts its followers to abstain from abusing idols of polytheists for it might excite them to abuse Allah in retaliation out of ignorance.