This white horse comes galloping to take away the souls at death.
From the blog, http://mythology.blogger.ba/
From all of the angels in Bosnian mythology only Azrail took the most intricate place because of the role which was given to him by Allah and that role encompasses taking souls from the human body. Because of such a task the humans are scared of him but make jokes about him at the same time, especially old people which comment "that Allah still hasn't sent them a telegram via Azrail" and that's why they are still alive. However, it is believed among the folk that Azrail's task of taking souls isn't easy since the soul is wrapped 99 times around each joint.
According to a story a man found out from a famous prophet on which day he will die and at what time and so struck with panic and wanting to live he decided to fool Azrail. As the prophet told him that he will die exactly at noon he mounted a horse half an hour before that time and galloped quickly towards the mountains, far away from his home believing that Azrail won't be able to find him. With a quick gallop and struck with panic the man pushed his horse to run as fast as he could so he can be as far away from his house as possible when the hour strikes noon. He rushed and rushed always looking behind to make sure that he went far away from his home. At that moment of inadvertency the horse tripped on a large rock, fumbled and fell into an abyss pulling his rider with it. The man died.
This story may not be a classic example of fatalism which is always present among the Bosnian folk. The start and end of life are predicted by Allah's will and no one can escape from it. That's why people believe that Azrail is the most intelligent of all angels since no one can trick him. It is also believed among the folk that Azrail can appear to someone in his/her sleep, in the form of a white horse. That's why it is said to the one who dreamt of a white horse that Azrail appeared to him as a messenger of death, and that someone close to him shall die.
It is interesting to say that according to Bosnian belief life and death both begin and end with the involvement of an angel. Namely, a child before it is born receives from an angel senet - a confirmation that when it is born it shall not die, to entice it to exit the mother's womb. But, as soon as it starts coming out he angels take away its senet and it is believed that this is the reason all children cry.