וַיַּכֵּ֥ר יוֹסֵ֖ף אֶת־אֶחָ֑יו וְהֵ֖ם לֹ֥א הִכִּרֻֽהוּ׃
José, pues, conoció á sus hermanos; pero ellos no le conocieron.
Ibn Ezra
He recognized … Yoseif recognized. He knew immediately that they were his brothers, but only after he examined them more carefully did he know who was who.
Ibn Ezra
הכרת. According to some, the cutting off, derived from כרת to cut off, but more correctly, the knowing of; comp. הכירהו they knew him (Gen. 42:8); the Dagesh in כ indicates the omission of the radical נ which appears in ינכר He is known (Prov. 26:24).12The first explanation is probably rejected, because הכרת would then be status constructus with the definite article ; and this is very exceptional. He who is able to judge of the constitution of the whole body from the face will find in it the declaration and confession of the truth; no further evidence is wanted.13Their evil designs are clearly written in their face, and easily to be discovered by those who are versed in reading countenances.
Ramban
THERE SHALL NO ‘BEN NEICHAR’ (ALIEN) EAT THEREOF. “This means one whose actions are estranged from his Heavenly Father, and applies both to a non-Israelite and an Israelite.”352In our Rashi: “an apostate Israelite.” Thus the language of Rashi quoting from the Mechilta.353Mechilta on the verse before us. The verse of course is needed only for the case of an [apostate] Israelite. And so did Onkelos translate: “There shall no ‘ben neichar’ eat thereof, i.e, any Israelite who has become an apostate,” meaning he has estranged himself from his brethren and from his Heavenly Father through his evil deeds.
This is the word neichar, mentioned by the Sages in all places, which means estranged, and the purport thereof is m’shumad, one who is a known [opponent to the Torah]. The usage of the word is similar to the Aramaic expression, ‘ve’isht’moda’ (And) Joseph (knew) his brethren, but they ‘isht’modei’ (knew) him not.354Genesis 42:8. In the case of the word m’shumad, it is missing the letter ayin, just as it is absorbed in many [Aramaic] words: midam (anything) in place of mida’am; dor kati in place of dor katia (a chopped generation),355Kethuboth 10b. baki in place of b’kia (expert).356Sanhedrin 5b.
This is the word neichar, mentioned by the Sages in all places, which means estranged, and the purport thereof is m’shumad, one who is a known [opponent to the Torah]. The usage of the word is similar to the Aramaic expression, ‘ve’isht’moda’ (And) Joseph (knew) his brethren, but they ‘isht’modei’ (knew) him not.354Genesis 42:8. In the case of the word m’shumad, it is missing the letter ayin, just as it is absorbed in many [Aramaic] words: midam (anything) in place of mida’am; dor kati in place of dor katia (a chopped generation),355Kethuboth 10b. baki in place of b’kia (expert).356Sanhedrin 5b.