From Heid1998 (<– Link to the article from which most of this post is copied):
In Sanskrit literature the Kalacakra tantra is unique in presenting a fairly comprehensive and quite accurate portrayal of Islamic beliefs and practices.
- “What, then, are the beliefs of the followers of Muhammad? The mleccha Tayin worship a mighty, merciless, demonic death-deity named arRahman (rahman). … By satisfying ar-Rahman a man achieves bliss in heaven; by displeasing ar-Rahman a man suffers in hell. At death a man is judged by ar-Rahman, and experiences his destiny in heaven or hell in that very corporeal human form. … The Tayin reject the Buddhist notion that a person’s experiences are the results of his karma; they reject the concept of reincarnation (1.10); and they deny that there is any sort of nirvana beside the achievement of heaven (1.14).”
- “The mlecchas slit the throats of animals while saying the mantra of their demonic deity Visavimla, ‘Withered by Poison’; that is, bismillah – “in the name of Allah” (1.1; cf. III.l).24 … Tayin ascetics dine after sundown and at night (1.6; IV.2).” “Mleccha prayer practices are also noteworthy. The Tayin first wash, then they bow down, five times each day: at noon, in the afternoon, in the evening, at midnight, and at sunrise (II.4). When praising their deity they kneel (1.6), and draw in their limbs like a tortoise (1.12). … The Tayin cut the skin from the tips of their penises26 as a cause for happiness in heaven” (IV.2). … Barbarian iconoclasm is also mentioned: the Tayin cavalry conduct raids to destroy Buddhist and non-Buddhist temples containing anthropomorphic images (II.4; cf. 11.5,6; 1.8).”
- “The Kalacakra tantra represents Islam as a religion of violence (himsadharma) that advocates savage behavior (raudra-karman) (1.6). …”
Buddhist Strategies for Dealing with Islam
- “First, the tantra prohibits its own adherents from participating in the barbarian religion. Second, it holds out the possibility of converting the barbarians to Buddhism. Third, it uses the threat of Islam in antibrahman polemics. Finally, it prophesies a Buddhist holy war against Islam.” (with an emphasis on the last)
- “There is no discernible attempt to portray Muslims as monsters by falsifying or distorting their ideology and behavior. On the contrary, the texts even report that the barbarians are truthful, clean, honest, and chaste. Although the authors clearly found Islam to be exotic and evil, they appear to have faithfully recorded their observations of it.”
- “Indeed, it is quite remarkable that in terms of comprehensiveness, detail, and accuracy the Kalacakra’s representation of Islam is superior to the sum total of pre-modern Muslim knowledge of Buddhism.”
- An esoteric/ spiritual meaning is ascribed to the Islam-Buddhist struggle.
- “Thus the Kalacakra’s representation of Islam can be viewed as an example of the tendency in classical Indian religions to represent historical events in mythic, trans-historical terms. “
- PS: These aspects of the kAlachakra teachings have been studied by attentive modern muslims, of course [forum].