‘Abdallah [b. Mas'ud] said: If any of you people knows anything he should make it known, but if anyone does not know he should say that God knows best, for saying this when one does not know is a part of knowledge. God said to His prophet, “Say, I do not ask you for any reward for it, and I am not a pretender.”* (Bukhari and Muslim.) *Qur’an, xxxviii, 86.