Abu Bakr was a great Sahabi who was also a dear friend of the Prophet (pbuh). Abu Bakr was known for his kind and gentle nature. He was very pious and loved Islam. He was very just and people would always turn to him for advice. He became the leader of the Muslims after the Prophet (pbuh) passed away.
Abu Bakr had a servant who was also a good friend. This servant would bring him some food with the money he had earned and Abu Bakr would eat it.
One day, the servant brought some food and Abu Bakr ate it as usual. The servant asked Abu Bakr if he knew where the servant had got this food from. Abu Bakr did not know so the servant started telling him the story.
In the days before Islam, the servant would sometimes do fortune telling for people and they would pay him money or give him gifts for it. This would bring him a little extra income.
That morning, the servant met a man who remembered him for telling his future. The man gave him some food as a gift for services in the past. This was the same food that the servant gave Abu Bakr to eat.
Abu Bakr immediately spat out the food he had in his mouth and also vomited whatever he had eaten from that food.
Islam had made fortune telling haram and any money earned from haram activity is also haram. Abu Bakr did not want any of this haram food to enter his body. He did not want to disobey Allah so avoided all haram and doubtful food