There are 3 kinds of oaths: Idle oaths which are not accountable, confirmed ones which are accountable, and false oaths which are cardinal sins and cannot be atoned for.

Oaths and Pledges

An oath is made to confirm something by Allah’s name or one of His attributes.[1] Oaths may be classified into three categories with respect to their validity and commitment.

1. Idle oath: This is when a person says the words of an oath without intending his statement as an oath. He may say, for example, ‘Yes, by Allah’, or ‘No, by Allah’, without intending his words to be an oath asserting what he is saying. This is called an ‘idle oath’, or to use the Arabic term, laghu. Alternatively, a person may say an oath confirming what he believes to be true, but he later realizes that it is false. Such oaths are taken as they are, the person saying them is not accountable for them, incurs no sin and there is no need to make any atonement for them.[2]  

   :Allah says

   ‘Allah does not impose blame upon you for what is unintentional in your oaths, but He imposes blame upon you for what your hearts have earned. And Allah is Forgiving and Forbearing.’ 

   (2:225)

2. Confirmed oath: This is an oath intended and insisted upon by the person saying it. It relates to future matters and refers to something possible. As this is a valid and intended oath, going back on it requires atonement.

   :Allah says

   ‘Allah will not impose blame upon you for what is meaningless in your oaths, but He will impose blame upon you for [breaking] what you intended of oaths.’ 

   (5:89)

3. False oath: A false oath is a major sin and is a lie intended to cheat, swindle other people’s rights or refute their rightful claims. The person saying it knows that he or she is telling a lie and it does not take place and cannot be atoned for, because it is too grave to be washed off by some atonement. In this respect, it is like the idle oath. However, the person who swears such an oath should repent and, if it results in denying people their rights, these rights must be returned to them. This oath is called an ‘immersing oath’ because it immerses the swearer in sin and leads him to hell.[3]  The basis of ruling that it is forbidden is the Qur’anic verse:

   ‘And do not take your oaths as [means of] deceit between you, lest a foot slip after it was [once] firm, and you would taste evil [in this world] for what [people] you diverted from the way of Allah , and you would have [in the Hereafter] a great punishment.’

   (16:94)

    :Ibn 'Umar quotes the Prophet (peace be upon him) as saying

   ‘The gravest sins are associating partners with Allah, being undutiful to one’s parents, murder and an immersing oath.’

   Related by al-Bukhari, hadith  No. 6,675