And our writer's point is to restate one of his foundational principles - "Without faith it is impossible to please him (God)..."(Hebrews 11:6). That principle includes Moses. God never ordained law as the means of pleasing Him. Even those under the law can't please God merely by law-keeping. God never imagined a pathway into His presence by law. Everything God does and says - including the law - must find its termination in the finished work of God the Son - the Christ - dying on the cross for our sins.
So as our writer continues to reason with these Hebrew Christians who are being pressed by their Jewish peers to come back under the law it is brilliant to bring up the person of Moses and link him to his faith. It was his faith that pleased God. So the faith of these Hebrew Christians isn't a new concept. And it isn't a break with either Abraham or Moses. These great patriarchs of Israel would be pleased with these Jewish believers for their faith in Christ.