Muslims believe that on any Friday, at the end of the week, a good deed is worth more than if you did that same good deed on a different day. Muslims go to the Mosque to pray on that day, for they believe that it was on this day that Adam was created. They reject the idea that God rested after creating the world ("And on the seventh day, God rested", Genesis 2:2) and so this day should not be related to a Sabbath.