The Sirat is the bridge over Hell that, in Islamic eschatology, every person must cross on the Day of Resurrection. The word in the Qur'an means simply path or way, it is the word of the opening chapter's petition, "guide us on the straight path" (1:6), and the eschatological bridge is developed chiefly in hadith and in the later creeds, where it becomes an article to be affirmed alongside the scales and the intercession.
The descriptions are vivid and consistent in outline: a bridge stretched over the Fire, said to be thinner than a hair and sharper than a sword, which the resurrected cross at speeds proportioned to their deeds. Some pass like lightning, some like the wind, some like a rider, some crawl, and some are seized by hooks and fall. The prophets stand at the crossing praying for their communities. Creedal texts such as the Aqida Tahawiyya list the Sirat among the realities to be believed without asking how.
The image has an evident relative in the Zoroastrian Chinvat bridge, the crossing of the separator, which is described as widening under the feet of the righteous and narrowing to a blade under the wicked. That parallel has been discussed since the nineteenth century, and Iranian influence on Islamic eschatological detail is a live question in the scholarship; the direction and extent of any borrowing are not demonstrable from the sources, and specialists differ. Within Islamic tradition itself the bridge is not treated as a borrowed image but as a disclosure about the structure of the judgement, and the moral point drawn from it is uniformly that the crossing is made by what one has already become.