بُلُوغُ الْمَرَامِ
Bulugh al-Maram 1134
Marriage
وَعَنِ اِبْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا قَالَ: { لَا رَضَاعَ إِلَّا فِي اَلْحَوْلَيْنِ } رَوَاهُ اَلدَّارَقُطْنِيُّ وَابْنُ عَدِيٍّ مَرْفُوعًا وَمَوْقُوفًا, وَرَجَّحَا اَلْمَوْقُوفَ [1] .
Narrated Ibn 'Abbas (RA): Suckling applies only (to infants) during the first two years (of their life). [Reported by ad-Daraqutni and Ibn 'Adi as Marfu' (a saying of the Prophet) and Mawquf (a saying of a Companion). However, they both held that the stronger view is that it is Mawquf (i.e. saying if Ibn 'Abbas).
Sunnah.com reference: Book 8, Hadith 198