Islam is such a pure religion that it does not permit the use of abusive language against any religious founder. The followers of other religions let out a stream of invective at the drop of a hat. Just look at how the Christians use foul language against the Holy Prophet, peace and blessings of Allah be upon him. If he had been alive today, even in view of his worldly status, they would not have had the courage to say a word against him. In fact, they would have treated the Holy Prophetsa with a thousand times more reverence. Such people would not dare curse or insult the Amir of Kabul or the Sultan of Rome, who are humble followers of the Holy Prophet, peace and blessings of Allah be upon him. But when the name of the Holy Prophet, peace and blessings of Allah be upon him, is mentioned, they revile him with a thousand obscenities. Islam is a benefactor for other religions because it vindicated every Prophet and divine scripture of the past. But despite this, Islam is abused. The essence of Islam لَا اِلٰہَ اِلَّا اللّٰہ There is none worthy of worship except Allah) is to be found in no other religion.
(Hazrat Mirza Ghulam Ahmadas, Malfuzat, Vol. 1, pp. 6-7)