(Those unto whom We gave the Scripture) those unto who We gave the knowledge of the Torah, i.e. 'Abdullah Ibn Salam and his followers (recognise (him)) Muhammad through his traits and description (as they recognise their sons. Those who ruin their own souls) through losing this world and the Next, i.e. Ka'b Ibn al-Ashraf and his followers (will not believe) in Muhammad or the Qur'an.