Ibn Majah

Commentary:
(1)
From these ahadith, it is understood that if a man is engaged in conjugal relations with his wife and, before ejaculation, he has to withdraw, then ritual bath (ghusl) is not obligatory. However, this ruling was in the beginning; later, it was abrogated. Now the ruling is that after intercourse, ritual bath (ghusl) is obligatory, whether ejaculation occurs or not, as is made clear by the narrations in the next chapter.

(2)
“The water is made obligatory by water” means that if, in a dream, one sees such a situation that would normally make ritual bath (ghusl) obligatory, but upon waking, no traces of it are found on the body or clothes, then there is no need to perform ritual bath (ghusl). Ritual bath (ghusl) is only necessary when its effects are actually present on the body or clothes, as will be mentioned in hadith: 612. In this sense, this hadith is not abrogated.

199. Commentary:

➊ In the early days of Islam, there was a concession that if a man separated from his wife before ejaculation while fulfilling marital relations, ritual bath (ghusl) was not obligatory upon him. This condition has been eloquently expressed as "water is due to water," meaning that ritual bath becomes obligatory upon the emission of semen (mani). However, this ruling was abrogated. Later, the Noble Prophet sallallahu alayhi wa sallam made ritual bath obligatory in every case after intercourse, whether ejaculation occurs or not. As Imam Muslim rahimahullah has established a chapter regarding the abrogation of this hadith and the obligation of ritual bath upon the meeting of the two circumcised parts of man and woman. See: [صحیح مسلم ، الحیض ، حدیث : 338]

➋ "Water (ritual bath) is due to water (emission of semen)." One meaning of this is that if, in a dream, a person sees such a situation that he feels he has experienced a wet dream (ihtilam), but upon waking finds traces of wetness on his body or clothes, then ritual bath becomes obligatory. However, if there are no traces of wetness, then there is no need for ritual bath. In this sense, this hadith is not abrogated; that is why Imam Nasa'i rahimahullah, using this as evidence, has established a chapter on this.