When Muhammad started the Muslim faith, he told his followers to pray while facing Jerusalem. Later, he changed his teaching, telling them to pray while facing Mecca. We can say that this was a symbolic break with the past because it symbolically told people that Judaism was now less important and Islam was more important.
Muhammad’s faith was and is a monotheistic faith. Islam understands itself as a relative of Judaism and Christianity, the other two major monotheistic faiths. Muhammad believed that Allah was the same God as the one that Abraham, Isaac, Jacob, and Jesus all worshipped. When Muhammad was starting his religion, then, it would have made sense to have people pray towards Jerusalem. This was the most important city in both Judaism and Christianity. If Muslims prayed in that direction, it would be a symbolic affirmation that they were part of that same faith tradition.
But then Muhammad told his followers to change and to face Mecca as they prayed. We can argue that this represents a break with the past because Muhammad is, in effect, saying that Judaism and Christianity are religions of the past. Muhammad is breaking away from them by no longer praying towards their holy city. Instead, he is having his followers pray towards Mecca, which is the center of the newest monotheistic faith, the one that (Muhammad believed) was more in line with what God really wanted than Judaism and Christianity were.