Hadith: O Messenger of Allah, if a man parts from his wife suddenly (during sexual intercourse) without discharging semen, what will he be required to do? The Messenger of Allah (may Allah's peace and blessings be upon him) said: It is water (seminal discharge) that makes water (ritual bath) obligatory

عن أبي سعيد الخدري رضي الله عنه قال: خَرَجْتُ مع رسول الله صلى الله عليه وسلم يوم الاثنين إلى قباء إِذَا كُنَّا فِي بَنِي سَالِمٍ وقف رسول الله صلى الله عليه وسلم على باب عِتْبَانَ فَصَرَخَ بِهِ، فَخَرَجَ يَجُرُّ إزاره، فقال رسول الله صلى الله عليه وسلم : «أَعْجَلْنَا الرَّجُلَ» فقال عتبان: يا رسول الله، أَرَأَيْتَ الرَّجُلَ يُعْجَلُ عن امرأته ولم يُمْنِ، ماذا عليه؟ قال رسول الله صلى الله عليه وسلم : «إِنَّمَا المَاءُ مِنَ الماءِ».
[صحيح] - [رواه مسلم]

Abu Sa‘īd al-Khudri (may Allah be pleased with him) reported: I went to Qubā’ with the Messenger of Allah (may Allah's peace and blessings be upon him) on Monday. On reaching (the locale of) Banu Sālim, the Messenger of Allah (may Allah's peace and blessings be upon him) stood at ‘Itbān’s door and called out to him loudly. He came out dragging his lower garment. When he saw that, the Messenger of Allah (may Allah's peace and blessings be upon him) said: "We made the man hurry." ‘Itbān said: "O Messenger of Allah, if a man parts from his wife suddenly (during sexual intercourse) without discharging semen, what will he be required to do?" The Messenger of Allah (may Allah's peace and blessings be upon him) said: "It is water (seminal discharge) that makes water (ritual bath) obligatory."
[Authentic hadith] - [Narrated by Muslim]

Explanation

This Hadīth that was reported by Abu Sa‘īd al-Khudri indicates that ritual bath becomes obligatory after ejaculation. The first 'water' mentioned in the Hadīth refers to seminal fluid, whereas the second "water" refers to water that is commonly known. The Hadīth indicates that the obligation of ritual bath is restricted to ejaculation and that no ritual bath is due when the two circumcised parts meet. However, this ruling was abrogated and ritual bath has become obligatory when sexual intercourse takes place, even if there is no ejaculation. This is proven by this Hadīth: "If the two circumcised parts meet, ritual bath becomes obligatory."