Abu Dawud

Benefits and Issues:
This was the effect of faith, piety, and fear of Allah that this Companion described this sin as equivalent to being burned or destroyed for himself.

Hadith Commentary:
This same incident is mentioned in detail further ahead, in which the Prophet (sallallahu alayhi wa sallam) instructed that person, as expiation (kaffarah), to fast consecutively for two months, or alternatively, to feed sixty needy people. From this, it is understood that this offense is a grave one, and its expiation is exactly as the Prophet (sallallahu alayhi wa sallam) has prescribed. The statement of Sa‘id ibn al-Musayyib and others means that, in addition to the aforementioned punishment, he must also make up this fast as obligatory upon him.
Imam al-Awza‘i (rahimahullah) said that if he fasts for two months, then making up (qada) the missed fast is not required.

Hadith Commentary:
(1)
This hadith indicates that the person deliberately had intercourse during the day in Ramadan, because one who does so out of forgetfulness is, by consensus, not sinful.

(2)
The meaning of “burning” is that, due to this sin, he will burn in the Fire on the Day of Resurrection.

Imam Malik has deduced from this narration that the only expiation (kaffarah) for breaking the fast in Ramadan through intercourse is to feed sixty needy people, and not to fast for two consecutive months or to free a slave. However, this deduction from the hadith is not correct, because this narration is abridged.

In the detailed narration, the Messenger of Allah (sallallahu alayhi wa sallam) said to him:
“Free a slave.”
He replied:
“I do not have the ability.”
You (sallallahu alayhi wa sallam) said:
“Feed sixty needy people.”
He said:
“I have nothing.”
Although fasting is not mentioned in this narration, it is explicitly stated in other narrations.
(Fath al-Bari: 4/208)

It should be clear that the order of expiation is as follows:
First, a slave should be freed.
If one is unable to do so, then two consecutive months of fasting should be observed.
If one is unable to do even that, then sixty needy people should be fed.
This expiation is obligatory upon the person who deliberately has intercourse with his wife while fasting.

There is no expiation for deliberately breaking the fast by eating or drinking, because the hadith pertains to intercourse, and it is not correct to make an analogy (qiyas) between eating/drinking and intercourse, since analogy is not applied in acts of worship.

Although there is a narration in which a man broke his fast and the Prophet (sallallahu alayhi wa sallam) prescribed this expiation, this narration is ambiguous (mujmal), and other narrations have clarified that he broke his fast through intercourse.
(Fath al-Bari: 4/211)

However, if one has intercourse out of forgetfulness, there is neither expiation nor making up (qada) required, as is mentioned in the hadith that if someone breaks his fast in Ramadan out of forgetfulness, there is neither making up nor expiation upon him.
(Al-Mustadrak lil-Hakim: 1/430)