Tafseer of The Winnowing Winds · Adh-Dhaariyat · 51:28
And he felt from them apprehension. They said, "Fear not," and gave him good tidings of a learned boy.
Important: The Arabic source text is always authoritative. This translation is a study aid and has not been verified by scholars — do not use it as a basis for religious proof or for deriving rulings (ahkam). When in doubt, always consult the Arabic text and a qualified scholar.
Then he conceived a fear of them — He says: then Ibrāhīm felt within himself a fear of his guests and concealed it. They said: fear not, and they gave him the glad tidings of a knowing boy — He means: Isḥāq. And He said: ʿalīm (knowing) carries the meaning of ʿālim (one who knows) when he has grown up. Al-Farrāʾ has mentioned that some of the old masters said: when the knowledge is anticipated, one says: he is assuredly a knowing one (ʿālim) after a short time and in the end; and concerning the lord (sayyid) one says sāʾid, and concerning the noble one (karīm) kārim. He said: and what he has said is correct. He said: and this too is good Arabic usage, which Allah has said with ʿalīm and ḥakīm and mayyit.
And it has been related from Mujāhid concerning His saying of a knowing boy what Muḥammad ibn ʿAmr related to me, saying: Abū ʿĀṣim related to us, saying: ʿĪsā related to us; and al-Ḥārith related to me, saying: al-Ḥasan related to us, saying: Warqāʾ related to us — both on the authority of Ibn Abī Najīḥ, on the authority of Mujāhid, concerning His saying of a knowing boy, he said: Ismāʿīl.
But I have said: He meant thereby Isḥāq, because the glad tidings were tidings of the child of Sāra, and Ismāʿīl was from Hāgar, not from Sāra.