Jinns are created from fire. Some jinns are given the power to shift shapes and take any form at will. Jinns usually have very long lives. Evil jinns are termed as Shayţān. They are also creatures similar to humans and they too have souls and [ethereal] bodies. They mate and reproduce; they also eat, drink, live and die.
Among the Jinn, there are Muslims and disbelievers [kāfir]; the proportion of those who disbelieve among them is greater than those among humans. Similar to humans, there may be pious or corrupt, and immoral individuals among jinn – or even Sunnis and heretics among them. The proportion of the evil ones among jinn are comparatively higher than the proportion of corrupt and unrighteous humans.
It is kufr to deny the existence of jinn – or to rationalise and claim that the ‘jinn’ refers to the evil that exists in humans.
Footnotes
The Arabic word jinn is singular, its plural is jānn. In English, we can use jinns as the plural or jinn-kind similar to humankind. This word is also spelled as djin, djinn, genie, djinni, jinnee, jinni and in the west, these are deemed as mythical beings. Heretical sects that imitate naturalists, such as Sir-Syed, have also denied their existence.
One of the arguments of naturalists [Naycharī] is that fire/flame is visible and a creature should also be visible. However, we now know that there are invisible flames such as a methanol fire. So it is not necessary that we believe in the existence of something only if it is perceived by human senses (or visible to the eye). Micro-organisms, various forms of radiation, sub-atomic particles exist, even though they cannot be perceived by human senses.
Plural: shayāţīn, which can be translated as the ‘devil’.
Sir-Syed rejected this outright in a monograph trying to disprove the existence of jinn, titled Tafsīr Jinn wa’l Jānn álā mā fi’l Qur’ān, in 56 pages, published in 1309 AH. On page 32 he says: “I have already explained in my commentary of the Qur’ān and I repeat it here...” and goes on to mention the description of Jinn as explained by scholars of Islām (as listed here) and finally says: “none of this is proven from the Qur’ān”.
According to Sir-Syed, ‘jinn’ refers to the propensity for evil in humans and ‘angels’ refer to the goodness in humans. See his Tafsīr al-Qur’ān, 1/52, published in 1903. 45