"The punishment of those who wage war against Allah and His Messenger, and strive with might and main for mischief through the land is: execution, or crucifixion, or the cutting off of hands and feet from opposite sides, or exile from the land: that is their disgrace in this world, and a heavy punishment is theirs in the Hereafter;" - Quran 5:33 (read more)

"Narrated Anas bin Malik: While we were sitting with the Prophet in the mosque, a man came riding on a camel. He made his camel kneel down in the mosque, tied its foreleg and then said: "Who amongst you is Muhammad?" At that time the Prophet was sitting amongst us (his companions) leaning on his arm. We replied, "This white man reclining on his arm." They then addressed him" - Sahih Bukhari 1:3:63 (read more)

"Ibn Sinna (Avicenna) was accused of being a Kafir and an atheist because of his statements about the antiquity of the world, his rejection of the Hereafter, and other atheist theories, in addition to his inner legendary ideology. Other scholars stated that Ibn Sinna was an atheist before Sheikh Al-Huwaini did; amongst them is: Al-Ghazali, Ibn Taymiyah, Ibn Al-Qayim, and Al-Dhahabi." - IslamWeb