Expiation is a general term referring to a type of physical or financial religious duty for someone that has violated a certain commandment and seeks forgiveness.
The expiation for an oath defines the religious duties of someone who has broken his/her oath.
The Almighty God commands the following about the expiation of an oath:
“God does not take you to task for the oaths you utter unintentionally, but He will certainly take you to task for the oaths you have sworn in serious intention. The expiation (for breaking such oaths) is the feeding of ten desperate persons with the average of what you feed to your own families, or to clothe them, or to set one subjugated person free from bondage. Who does not find the means, shall fast for three days. This is the expiation for your oaths whenever you have broken them. But do keep your oaths. Allah makes clear to you His commandments, so that you may fulfill your duties.” (Al-Maidah / The Feast 5:89)
As it can be seen in the verse, the main thing is to keep the promises. (Please see other verses about this subject: An-Nahl / The Bee 16:91-95) However, sometimes the oaths need to be broken, even ordered so; and sometimes the oaths cannot be kept for certain reasons. Obviously, an expiation becomes necessary in these situations. It has been narrated that the Messenger of Allah said the following about this issue:
“If you take an oath to do something then see some other thing as better; break your oath, expiate for it and go for the better way.” (Bukhari, Ayman/Vows, 1; Muslim, Ayman/Vows, 11 (1650))
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