How authentic is this hadith: "And if you turn away, He will substitute in your place another people," so they said, "O Messenger of Allah, who are the people whom, if we turn away, He will substitute in our place?" Then the Messenger of Allah struck the knee of Salman al-Farisi (may Allah be pleased with him), [saying,] "This one and his people... By Him in Whose hand is my soul, even if faith were tied to the Pleiades, men from Persia would attain it?"

The hadith in question is authentic, narrated by Al-Tirmidhi, Ibn Hibban, and others. Its wording, from Abu Hurairah, states that when the Prophet, peace and blessings be upon him, was asked about: {And if you turn away, He will replace you with another people; then they will not be the likes of you} [Muhammad:38], he struck Salman al-Farsi's thigh and said: "This man and his companions. By Him in whose hand is my soul, were faith tied to the Pleiades, men from Persia would surely reach it." Al-Albani and others have authenticated this hadith, and there are many corroborations of its truth in the imams of Islam who were of Persian origin.