Their evidence is that Allah has linked the prohibition to the very term riḍāʿa (nursing). In the Quran the word is left unqualified; therefore, wherever the term is found, its ruling applies.
A second group held that the impediment to marriage is not established by fewer than three feeds. This view is attributed to Abū Thawr, Ibn al-Mundhir, and Dāʾūd.
Their proof is the authenticated ḥadīth in which the Prophet ﷺ said, “A single suckle does not create the prohibition, nor do two.” [Muslim]
The purport of the ḥadīth is that anything beyond two suckles—namely three or more—does establish the prohibition.
A third group maintained that the bar to marriage is not established by fewer than five feeds. This is the position of ʿAbd Allāh ibn Masʿūd, ʿAbd Allāh ibn al-Zubayr, ʿAṭāʾ, Ṭāwūs, and it is the school of al-Shāfiʿī, Aḥmad, and Ibn Ḥazm.
Their evidence is the report in Ṣaḥīḥ Muslim in which ʿĀʾishah (may Allah be pleased with her) said, “Among what was revealed in the Quran was: ‘Ten well-known sucklings render marriage unlawful.’ Then it was abrogated by ‘five well-known sucklings,’ and the Messenger of Allah ﷺ passed away while it was still being recited as part of the Quran.”
They also cite the narration in Ṣaḥīḥ Muslim concerning Sahlah, the wife of Abū Ḥudhayfah. She said: “We used to regard Sālim as our son; he stayed with me and with Abū Ḥudhayfah in one house and would see me uncovered. Allah has revealed about them what you know, so what do you rule concerning him?” The Prophet ﷺ replied, “Breast-feed him.” She therefore suckled him five times, and he assumed the status of her son through nursing.
This group answered the arguments of the first two groups as follows: As for those who hold that both a small and a large number of sucklings create the prohibition, the answer is the sound ḥadīth already cited: “A single suckle does not create the prohibition, nor do two.”
Regarding the advocates of three feeds, their evidence rests on implied meaning, whereas explicit wording takes precedence. Acting upon the reports that stipulate five sucklings harmonizes all the ḥadīths together.