What are the sources of the prohibition based on suckling (Rada'ah)?
General Chapter
Al-Mughni
Book of Fosterage (Breastfeeding)
Primary text
The prohibition established through suckling is founded upon the Book (Quran), the Sunnah, and the consensus (Ijma') of the Ummah. The Quranic evidence is the statement: "And your mothers who have suckled you, and your sisters from suckling" (Quran 4:23), where the mother and sister are mentioned among the prohibited degrees. The Sunnah evidence includes the Prophet's saying, reported by Aisha, "Suckling establishes what lineage establishes in terms of prohibition," which is agreed upon (Muttafaqun Alayh). Another narration states, "What is prohibited by lineage is prohibited by suckling," reported by An-Nasai. Furthermore, the consensus of the scholars of the nation on this prohibition is established.
Supporting text
The prohibition of the mother and sister is established by explicit text, while the prohibition of the daughter is established by implication, as she is more closely related than the sister. The prohibition of the rest of the relatives is established by the Sunnah. Affinity established through suckling is a branch of prohibition, provided the suckling occurred through a permissible means. However, other rulings of lineage, such as financial maintenance (Nafaqah), manumission, and rejection of testimony, do not apply, as lineage itself is considered stronger and cannot be fully analogized to suckling in all its rulings.