Ubayy bin Kaab reported: The Messenger of Allah ﷺ made a concession in the early days of Islam on account of the paucity of clothes that one should not take a bath if one has sexual intercourse (and has no seminal emission). But later on her commanded to take a bath in such a case and prohibited its omission.
Related hadith on this topic
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
➊ The detail of this issue is that, in the early period of Islam, it was permitted for spouses that, at the time of intercourse, if ejaculation (inzal) did not occur, ritual bath (ghusl) was not obligatory. This condition was expressed in an eloquent manner: “Water is (obligatory) because of water.” That is, the water of ritual bath becomes obligatory only upon the emission of the water of semen (mani). However, this ruling was abrogated, and it was stated: “When the circumcised part meets the circumcised part, then ritual bath becomes obligatory,” as is mentioned in the following ahadith. Therefore, the aforementioned words and rulings are now specific to the case of a wet dream (ihtilam). That is, if something is seen in a dream and wetness or traces are apparent on the body or clothes, or if semen is discharged in any other way, then ritual bath will be obligatory; otherwise, it will not. However, after intercourse with one’s wife, ritual bath is obligatory in every case.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 215