When a person swears by Allah that he’ll do something in the future; then that is considered in Islam as an oath that must be fulfilled as long as it is in obedience to Allah (i.e. does not involve sin). If however, fulfilling the oath involves disobedience to Allah and His Messenger (ﷺ) or he sees that something else is better in its place, then he should break his oath and oppose what he swore to do. This is due to the saying of Allah’s Messenger (ﷺ): “Whoever vowed to obey Allah, then let him obey Allah. And whoever vowed to disobey Allah, then he must not disobey Him.” (Bukhāri, 6696) And due to the saying of the Messenger (ﷺ): “Whoever took an oath to do something, then he sees that to do something else is better than it, let him expiate for the broken oath, and do what he sees is better.” (Muslim, 1650)
Based upon this, if a person opposes what he swore (by Allah) that he would do, he must expiate for breaking each oath he did not carry out ―if those oaths pertained to different acts. However, if the oath was related to one deed he swore he would do, that he repeatedly broke, then he expiates just once to cover the repeated violations of one oath. The expiation is as follows:
- Feed ten poor people or clothe them.
- Or free a believing slave.
- And if one is unable to do that, then fast for three days (the three days can be consecutive or separated).
This is in accordance with the saying of Allah, the Most High:
لَا يُؤَاخِذُكُمُ اللَّهُ بِاللَّغْوِ فِي أَيْمَانِكُمْ وَلَٰكِن يُؤَاخِذُكُم بِمَا عَقَّدتُّمُ الْأَيْمَانَ ۖ فَكَفَّارَتُهُ إِطْعَامُ عَشَرَةِ مَسَاكِينَ مِنْ أَوْسَطِ مَا تُطْعِمُونَ أَهْلِيكُمْ أَوْ كِسْوَتُهُمْ أَوْ تَحْرِيرُ رَقَبَةٍ ۖ فَمَن لَّمْ يَجِدْ فَصِيَامُ ثَلَاثَةِ أَيَّامٍ ۚ ذَٰلِكَ كَفَّارَةُ أَيْمَانِكُمْ إِذَا حَلَفْتُمْ ۚ وَاحْفَظُوا أَيْمَانَكُمْ ۚ كَذَٰلِكَ يُبَيِّنُ اللَّهُ لَكُمْ آيَاتِهِ لَعَلَّكُمْ تَشْكُرُونَ – 5:89
“Allah will not impose blame upon you for what is unintentional in your oaths, but He will impose blame upon you for [breaking] what you intended of oaths. So its expiation is the feeding of ten needy people from the average of that which you feed your [own] families or clothing them or the freeing of a slave. But whoever cannot find [or afford it] – then a fast of three days [is required]. That is the expiation for oaths when you have sworn, and guard your oaths. Thus does Allah make clear to you His verses that you may be grateful.” (Al-Mā’idah: 89)
It is not allowed for a Muslim to be easy-going with his oaths so that he avoids having to expiate for them after breaking them ―or that he is always swearing by Allah [that he will do this and that] for no need. Allah has stated: “And guard your oaths.” Meaning: Don’t keep swearing by Allah.
See, Al-Jāmi’ fī Fiqhil-‘Allāmah Ibn Bāz (p. 1082), slightly adapted.