“They ask you, ‘Is it true?’ Say, ‘Yes, by my Lord, it is indeed true, and you cannot escape.’” [Jonah: 53]

And in Surah al-Taghābun:

“Those who disbelieve claim that they will never be resurrected. Say, ‘Yes, by my Lord, you will surely be resurrected; then you will surely be informed of what you did. That is easy for Allah.’” [al-Taghābun: 7]

And in Surah Saba’:

“Those who disbelieve say, ‘The Hour will not come upon us.’ Say, ‘Yes, by my Lord, the Knower of the unseen, it will surely come upon you. Not even an atom’s weight in the heavens or the earth escapes Him, nor is there anything smaller or greater than that without being recorded in a clear Book.’” [Saba’: 3]

These are the oaths that Allah Most High commanded us to guard, saying:

“Guard your oaths.” [al-Mā’idah: 89]

He also prescribed expiation for them, saying:

“Allah will not hold you accountable for your inadvertent oaths, but He will hold you accountable for the oaths you bind yourselves by. Their expiation is to feed ten needy people with food of the average quality you feed your families, or to clothe them, or to free a slave. Whoever cannot afford this must fast for three days. That is the expiation for your oaths when you have sworn.” [al-Mā’idah: 89]

This means: when you have sworn and then broken your oath. That is what the passage implies.

Disliked oaths are those sworn by other than Allah Most High, for the Messenger of Allah ﷺ said to ‘Umar ibn al-Khattāb—may Allah Most High be pleased with him—“Allah forbids you to swear by your fathers. Whoever wishes to swear should swear by Allah or remain silent.”

These fall into two categories: those that are not binding and those that are binding. A binding oath is one in which a person undertakes to divorce, emancipate a slave, do something of a similar nature, or perform an act that draws him nearer to Allah Most High, if he does something or fails to do it.

A nonbinding oath is one in which a person undertakes to commit a sin, or to do something that constitutes neither obedience nor disobedience to Allah, if he does something or fails to do it. For example, he might say, “If I do such-and-such, or fail to do it, I undertake to drink wine, kill so-and-so, walk to the market,” or something similar. Alternatively, he may invoke something other than Allah Most High in an oath, saying, for example, “By the mosque,” “By the Messenger,” “By Mecca,” “By prayer,” “By zakat,” or the like.