The Muslim scholars have agreed that a group resisting compliance must be fought if it refuses to observe some of Islam’s manifest obligations established by mass transmission. If they profess the two testimonies of faith but refuse to perform prayer and pay zakah, fast the month of Ramadan, make pilgrimage to the Ancient House, judge among themselves according to the Quran and Sunnah, prohibit sexual immorality, wine, or marriage to women within the prohibited degrees of kinship, or [prohibit] treating lives and property as lawful to violate without right, usury, or gambling, or wage jihad against the unbelievers, or impose jizyah on the People of the Book, or observe other such laws of Islam, then they are to be fought over these matters until religion is entirely for Allah.

It is established in the two Sahīh collections that when ʿUmar debated with Abū Bakr concerning those who withheld zakah, Abū Bakr said to him:

“How could I not fight those who abandon the dues that Allah and His Messenger have made obligatory, such as zakah, even if they have embraced Islam?” He also told him: “Zakah is among its rightful dues. By Allah, if they withheld from me a young she-goat that they used to give to the Messenger of Allah—may Allah bless him and grant him peace—I would fight them for withholding it.”

ʿUmar said:

“As soon as I saw that Allah had opened Abū Bakr’s heart to fighting, I knew that it was right.”

It is also recorded in the Sahīh through several routes of transmission that the Prophet—may Allah bless him and grant him peace—mentioned the Kharijites and said of them:

“Any one of you would consider his prayer insignificant beside theirs, his fasting beside theirs, and his recitation beside theirs. They recite the Quran, but it does not go beyond their throats. They pass out of Islam as an arrow passes through its quarry. Wherever you encounter them,