I'll list here some evidences:
It has been made permissible for you the night preceding fasting to go to your wives [for sexual relations]. They are clothing for you and you are clothing for them. Allah knows that you used to deceive yourselves, so He accepted your repentance and forgave you. So now, have relations with them and seek that which Allah has decreed for you. And eat and drink until the white thread of dawn becomes distinct to you from the black thread [of night]. Then complete the fast until the sunset. And do not have relations with them as long as you are staying for worship in the mosques. These are the limits [set by] Allah , so do not approach them. Thus does Allah make clear His ordinances to the people that they may become righteous. (2:187)
This verse clearly shows that Allah knows the effort we made by denying our desires during the day of Ramadan and that we are allowed to have legal relations with our wives during the night times. It also shows that we should even deny our lusts more if we are doing I'tikaf (staying for worship in the mosques).
I and Masruq went to 'A'isha (Allah be pleased with her) and asked. her if the Messenger of Allah (ﷺ) embraced (his wives) while fasting. She said: Yes; but he had the greatest control over his desire among you: or he was one of those who had control over his desire. (see for example in sahih Muslim)
The Prophet (ﷺ) used to kiss and embrace (his wives) while he was fasting, and he had more power to control his desires than any of you. (Sahih al-Bukhari)
This hadith is used as an evidence for all those who say that kissing between spouses is allowed. It basically allows even more. But most scholars who say so say a person should be able to control his desires!
This can also be concluded from this hadith:
A man asked the Prophet (ﷺ) whether one who was fasting could embrace (his wife) and he gave him permission; but when another man came to him, and asked him, he forbade him. The one to whom he gave permission was an old man and the one whom he forbade was a youth. (Sunan abi Dawod)
Therefore some scholars prohibited it as the hadith says that the prophet had the greatest control over his desire which doesn't apply to us!
On the goals of fasting
Among the reasons and goals of fasting you may find:
- By refraining from some of our desires (halal food, beverage and sexual relationships) we may learn to appreciate them more and therefore be able to consider them even more as gifts from Allah: So we may be lead to thank Allah for his gifts!
- If we learn to give up and refrain from halal things we may also and even more learn -by fasting- to give up haram things. This is another educational goal of fasting!
- Another educational goal of fasting is to teach us to have control over our desires as a person with a full stomach may have a growing desire while an empty stomach wouldn't encourage us to follow our lust.
- Fast also makes us feel passion and empathy for poor people and those who can hardly feed themselves and those they are inn charge of.
- As nobody but Allah really knows whether we fast or not, fasting trains us to remember Allah and remember Him, it also make us come close to the level of Ihsan:
"Ihsan is to worship Allah as if you see Him, and if you do not achieve this state of devotion, then (take it for granted that) Allah sees you." (See for example in sahih al-Bukhari)
- By fasting we train ourselves on a kind of asceticism towards worldly matters.
- By fasting we train our soul by doing more worship then during our usual days so it is a concentration on our souls.
- Fasting also teaches us patience in all matters.
Therefore we should ask ourselves why would we even think about following our lusts, when we would have the chance to follow them on the same day is it that difficult? Have we already failed in an early stage to reach the level of Ihsan ...
Some related rulings
From the given evidences we know that anything, but intercourse is basically allowed as long as we have control on our selves, so what are the limits and what are the rulings when we've got to far?
As when we go to far we may reach a couple of undesirable "goals":
- having committed a sin.
- invalidated our fast.
- need to make up this fast.
- need to pay a kafarah.
- and we will need to complete the day fasting nevertheless!
Here some basic rulings:
In case of real intercourse (with penetration) a kafarah is necessary. Scholars discussed the matter of a wife who couldn't stop her husband and said only the husband needs to pay it (and depending on her situation she might or might not even need to make up that day).
If any of the spouses ejaculates (without penetration) -only- this person needs to make up that day of fast as the fast is invalid. Note that some madhhabs (hanbali, maliki) even consider madhy as the ejaculation invalidating the fast.
A person who ejaculated without having intercourse, kissing ... or touching the spouse for example by day dreaming or during a wet dream only needs to perform ghusl. As this person had no real intercourse nor anything leading to it.
Nevertheless it is strongly encouraged to keep away of anything which may lead to have intercourse while fasting. And strongly discouraged to put oneself in such a situation where one may loose control!