Disbelief (kufr)

Kufr is concealing in the lexicon, the opposite of faith; in law it is denying what is known by necessity of the religion of Muhammad, such as denying the Creator, the prophecy of the Prophet ﷺ or the prohibition of adultery ¹.

Riddah is a Muslim's disbelief by a clear word or act; kufr is wider, since it can be original disbelief. Shirk is wider than kufr, since it includes sharing in dealings. Ilhad is turning from the straight law toward some form of disbelief ².

Disbelief is forbidden and is the gravest sin; the penalty of the disbeliever in the next world is eternal Fire ². In this world the combatants among the disbelievers may be killed, but women, children, the insane and, according to most jurists, the elderly may not; a farmer who does not fight is not to be killed ³.

A man forced to utter the word of disbelief is not a disbeliever if his heart remains at peace with faith. Hanafis require complete coercion; Malikis allow the utterance only under threat of death; Shafi'is allow it while the heart is at peace; Hanbalis do not declare apostasy when the coercion is proved. Patience and steadfastness are better even under threat of death ^{3 4 5}.

Al-Kasani divides disbelievers into four: those who deny the Creator (the materialists), the idolaters and Magians, the philosophers who deny prophecy, and the Jews and Christians who deny the prophecy of Muhammad ⁶. Some disbelief is agreed on, such as associating others with God or denying a known necessity; other kinds are disputed ⁶.

The majority allow addressing them by reason. As for the law, there are three views: they are addressed by all duties on condition of faith; they are not addressed by the duties at all; they are addressed only by the prohibitions ^{6 7 8}.

The Muslims must call disbelievers to Islam before fighting them; if they accept, they are left alone; if they refuse, they are offered the protection of the poll tax where it is accepted; if they refuse that too, the Muslims fight, trusting in God ^{8 9}.

Debts for sales, rents and loans fall on a convert. A non-Muslim who is in a protected status owes for all wrongs, while a hostile disbeliever is excused from usurpation and plunder. God's rights, such as vows, oaths, prayers and zakat missed before conversion, fall away, on the hadith that Islam destroys what came before it ^{8 9}.

Islam urges kindness to disbelieving parents ⁹. A living disbeliever is pure, since he is human; the impurity of the idolaters refers to their belief ¹⁰. A disbeliever may not touch the mushaf, according to the Malikis, Shafi'is, Hanbalis and Abu Yusuf; Muhammad allows it after washing ¹⁰. Disbelievers are barred from the Sacred Mosque by the Malikis, Shafi'is, Hanbalis and Muhammad; the Hanafis allow entry; outside the Sacred Mosque the Malikis forbid and a Hanbali narration forbids it ^{10 11}. A dying disbeliever is prompted to say the testimony, as a duty if hope of his conversion exists ^{11 12}.

A disbeliever has no guardianship over a Muslim, and may not marry off his Muslim daughter; he may not be a judge over Muslims, though Abu Hanifa allowed judging among his own people ¹². The marriages of disbelievers are valid if they convert or come to our courts ^{12 13}. Marrying idolaters is forbidden; marrying women of the Book is allowed but disliked; a Muslim woman may not marry a disbeliever ^{13 14}. A disbeliever's bequest is valid, and hire from or to a disbeliever is valid, and a dhimmi may hire a Muslim for a specified task ¹⁵.

The Malikis and Hanbalis allow partnership with a disbeliever, on condition that he does not deal in wine or pork ¹⁶. Disbelievers may not be enlisted in war except when needed, on the report of Aisha about the man the Prophet turned back until he became a Muslim ¹⁶. A disbeliever may endow to a Muslim or to a non-Muslim, provided it is not for a sin ¹⁶.