It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that he said: When a woman carries the child for nine months, she will breastfeed it for twenty-one months; and if she carries it for six months, she will breastfeed it for twenty-four months. Then, as proof of this, he recited this verse: "And his bearing and his weaning are thirty months" [Surah al-Ahqaf: 15] . This hadith has a sahih (authentic) chain of narration, and the two Shaykhs (Bukhari and Muslim) did not record it.