Excerpts from the ‘Jurisprudence of Worship’
By Shaykh Muhammad ibn Saalih ibn Uthaymeen رحمه الله تعالى

Question: Oh Noble Shaykh, What is the ruling of intercourse during the day in Ramadān for the one who is mindful (of his state of fasting) and for the one who is forgetful (of his state of fasting)?

Answer:

Intercourse during the day in Ramadān is similar to other invalidators of fasting. However, in the case of a person who is travelling there is no harm in that (intercourse) for him if he was fasting in his travels or not. As for the one whom fasting is obligatory upon, if he was forgetful (of his state of fasting during intercourse) then nothing is upon him as well. Similarly to all invalidators of fast, if a person forgets (he is fasting) and he happens to fall into any of them, then his fast is correct. As for the case where he is mindful (of his state of fasting) and remembers and he is fasting then five matters become imposed upon him:

1) The sin (of breaking one’s obligated fast in the days of Ramadān without a valid excuse)
2) Breaking fast (prematurely therefore no reward in fasting that day)
3) The obligation of continuing fasting (for the rest of day until sunset)
4) Fasting and making up this day of fasting on another day
5) Expiation

Expiation (of having intercourse during the day in Ramadān) is to emancipate a slave, if not then to fast 2 months consecutively and if he is not able to, then he is to feed 60 needy people.

By the hadeeth narrated by Abi Hurrairah رضى الله عنه : “Verily a man came to Prophet ﷺ O Allah’s Messenger ﷺ! I have been ruined.” Allah’s Messenger ﷺ asked what was the matter with him. He replied “I had sexual intercourse with my wife while I was fasting.” Allah’s Messenger ﷺ asked him, “Can you afford to emancipate a slave?” He replied in the negative. Allah’s Messenger ﷺ asked him, “Can you fast for two successive months?” He replied in the negative. The Prophet ﷺ asked him, “Can you afford to feed sixty poor persons?” He replied in the negative. The Prophet ﷺ kept silent and while we were in that state, a big basket full of dates was brought to the Prophet ﷺ. He ﷺ asked , “Where is the questioner?” He replied, “I (am here).” The Prophet ﷺ said (to him), “Take this (basket of dates) and give it in charity.” The man said, “Should I give it to a person poorer than I? By Allah; there is no family between its (i.e. Madinah’s) two mountains who are poorer than I.” The Prophet smiled till his premolar teeth became visible and then said, ‘Feed your family with it.”

Related by Bukhari – The Book of Fasting-Number [1936] and related by Muslim – The Book of Fasting-Number [1111].
Jurisprudence of Worship- Fatwa Regarding Sâum (Fasting). By Shaykh Muhammad ibn Saalih Ibn Uthaymeen (pg.278-279)

Translated by: Abu Uwāis, Muhammad Abdullahi Elmi