Does swearing break the fast?

Detailed answer

Swearing does not invalidate your fast. The things that break a fast are well known: eating, drinking, intimate relations and similar acts. Bad language is not one of them, so your fast still counts and you do not need to make it up. But swearing is a sin, and it can empty the fast of its reward, which is the very thing you are fasting for.

What the Sunnah says

The Prophet said: "Fasting is a shield. When one of you is fasting, he should not use obscene language or behave foolishly. If someone fights him or insults him, let him say: I am fasting" (Bukhari and Muslim). He also said that whoever does not give up false speech and acting on it, Allah has no need of him giving up his food and drink (Bukhari).

In another narration he warned that some people who fast get nothing from their fast except hunger (Ibn Majah). Scholars explain that this refers to those who keep away from food but not from sins of the tongue.

What to do if you slip

• Say astaghfirullah (I ask Allah's forgiveness) straight away and carry on with your fast.
• If you swore at a person, apologise to them. Hurting someone is a right owed to them, not only to Allah.
• Follow a bad word with a good deed. Allah says that good deeds do away with bad deeds (Hud 11:114).

Tips to break the habit

• Notice your triggers: traffic, games, work pressure. Prepare a replacement phrase such as subhanallah or la hawla wa la quwwata illa billah.
• Ask a friend or family member to remind you gently when you slip.
• Remember that anger is stronger when you are hungry and tired. Good sleep and a proper suhoor help.
• If someone provokes you, follow the Prophet's advice in what to do if someone insults you.

The same principle applies to other sins of the tongue; see lying and backbiting while fasting. Think of Ramadan as a month-long training course: a tongue that stays clean for a month can stay clean for life.