Why do Muslims run in the middle of 2 hills in Mecca?

Answer 1

This running between the hills (hills of Safa and Marwah) is called Sai.

To understand this, the story of Abraham needs to be understood. Abraham was married to Sarah and could not have children with her so she offered her attendant Hagar as a wife to Abraham with whom he had a son named Ishmaeel. Sarah eventually became jealous and wanted them "gone" so Abraham asked God for guidance and it was revealed to Abraham to take Hagar and her son to a certain location in the desert and leave them there. Abraham did as God had commanded him to do.

Hagar and her young son Ishmaeel were left in the desert all alone where there was nothing (not even a camp). The little water they had ran out and Hagar started to look for water for her little son. There were two hills on either side of them and she decided to climb one of the hills to see if she could find any place where she could get some water. As she climbed the top of one of the hills she did not find any source of water but also noted that she lost sight of her little baby so she ran back down the hill and saw that her son was safe. Then she climbed the other hill hoping that she might chance some water that way. From the top of that hill she also could not see her son and so she quickly ran back down until she saw that he was safe. So she would go back up the other hill and then run back and then the other hill and run back down. Eventually, God granted them the gift of water by letting a spring gush out where the young Ishmaeel's heels were rubbing in the sand. She saw the water gushing and ran to him and realized that the water continued to gush and would not stop. Thus she yelled "Zam, Zam (stop, stop)" and the gushing stopped. She eventually built a wall around the water to contain it. That source of water is the ZamZam water in the Holy Harm in Makkah.

Thus to commemorate this motherly act do Muslims perform Sai by running between the hills of Safa and Marwah during the annual Hajj.

F.Y.I. The other rituals of Hajj also involve homage to Abraham such as the sacrifice that he almost made of his son as well as the stoning of the three pillars of satan to commemorate the three times that he was tempted by satan to abandon God and he threw stones at satan so that satan would go away and leave him alone.