The second view: any suckling that takes place while the child is still an infant, without fixing a specific age limit.
The third: suckling renders marriage unlawful even when it involves a full-grown adult or an elderly man.
The fourth: suckling is not prohibitive except in infancy—unless a genuine need requires nursing an adult whose presence in the household is indispensable and from whom it would be unreasonably difficult to maintain seclusion.
Those who held the first view include al-Shafiʿi, Ahmad, and the two disciples of Abu Hanifah, Abu Yusuf and Muhammad ibn al-Hasan. It is authentically reported from ʿUmar, Ibn Masʿud, Abu Hurayrah, Ibn ʿAbbas, and Ibn ʿUmar; it is also narrated from al-Shaʿbi and is the opinion of Sufyan, Ishaq, and Ibn al-Mundhir.
Their evidence is the Almighty’s statement: “Mothers shall nurse their children for two complete years for whoever wishes to perfect the nursing” (Quran 2:233). Since the Qur’an fixes the completion of nursing at two years, anything beyond that carries no legal consequence and therefore does not create a prohibition.
They also cite the previously mentioned hadith, “Suckling that establishes kinship is only the suckling that allays hunger,” noting that the period of such hunger is within the two years.
Al-Darqutni likewise transmits with a sound chain from Ibn ʿAbbas, traced back to the Prophet ﷺ: “No suckling counts except what occurs within the two years.”
In Sunan Abu Dawud, Ibn Masʿud reports—traced back to the Prophet ﷺ—“Nothing from suckling produces prohibition except that which causes flesh to grow and bone to strengthen.”
Suckling an adult neither grows flesh nor strengthens bone.
Those who adopted the second opinion were the Mothers of the Believers—apart from ʿĀʾishah—and it is also narrated from Ibn ʿUmar and Saʿid ibn al-Musayyib.
Their proof is the report found in both Ṣaḥīḥs in which the Prophet ﷺ said, “Suckling that establishes kinship is only the suckling that allays hunger.” Its general wording implies that as long as a child’s sustenance is milk, such nursing is prohibitive. This is a sound line of reasoning with a strong foundation.
A number of early and later scholars embraced the third position, among them ʿĀʾishah.