Tafsir Ibn Kathir (abridged)
The Birth of the Boy and His Characteristics
This also implies what is not mentioned, that this promised boy was born and he was Yahya. There is also the implication that Allah taught him the Book, the Tawrah which they used to study among themselves. The Prophets who were sent to the Jews used to rule according to the Tawrah, as did the scholars and rabbis among them. He was still young in age when Allah gave him this knowledge. This is the reason that Allah mentioned it. Because of how Allah favored him and his parents, He says,
ييَحْيَى خُذِ الْكِتَـبَ بِقُوَّةٍ
(O Yahya! Hold fast to the Scripture the Tawrah.) Means, "Learn the Book with strength." In other words, learn it well, with zeal and studious effort.
Continue reading the tafsir of ayahs 12–15