Sayyiduna Safwan bin Assal al-Muradi (may Allah be pleased with him) says that one of two men from the People of the Book said to the other: Let us go to this prophet. The other said: Do not let him hear this, or he will have four eyes (he will be overjoyed). They came to him and asked him about nine clear signs, and the Prophet (peace and blessings be upon him) said: "Do not associate anything with Allah, do not kill, do not steal, do not commit adultery, do not practise magic, do not consume usury (riba), do not slander chaste women, do not flee from the battle, and do not take an innocent person to a ruler so that he kills him; and particular to you, O Jews, is that you do not transgress regarding the Sabbath." Then the two of them kissed his (peace and blessings be upon him) hands and feet and said: We bear witness that you are a prophet. He (peace and blessings be upon him) asked: "What prevents you from following me?" They said: Dawud (peace be upon him) prayed that a prophet would always be from his offspring, and we fear that if we follow you, the Jews will kill us.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قتال أهل البغي / 16673