It provides a different opinion on topics that people believe in and to better what we do as a society and to better ourselves we must challenge our thinking and be open to new experiences because that is how we learn
Both sides agreed that Allah is the one true God and that Muhammad was his messenger, but one group (which eventually became the Shiites) felt Muhammad's successor should be someone in his bloodline, while the other (which became the Sunnis) felt a pious individual who would follow the Prophet's customs was acceptable.
It's Rebuff
since reboof and rebaff are not words