And in the four and twentieth day of the first month, as I was by the side of the great
river, which is Hiddekel... Daniel 10:4
"By the River Hiddekel the Syriac understands the Euphrates;
the Vulgate, Greek, and Arabic, the Tigris;
hence Wintle concludes that the prophet had this vision at the place where these rivers unite, as they do not far from the Persian Gulf." Uriah Smith