quran, 20:22 And make close your hand to your side, it shall come forth crystal white with out any disease as one more sign. pir sayyid abdul qadir jilani said that imam nasafi asks a question: when musa 'alaihis salam saw Allah during one of his journeys; why was he given the miracle of yad e bayda when there were no kuffar present? miracles are given as an answer to the deniers. the imam writes that it was to help the yaqeen of musa 'alaihis salam that it is indeed Allah Who is speaking to him. --- i feel this is like the prophet ibrahim's question rabbi arini kayfa tuHyil mawtaa?but, in musa 'alaihis salam's case, Allah gave the proof without enquiry whereas ibrahim 'alaihis salam asked himself. quran, 2:260 And when Ibrahim submitted, 'O my Lord, show me how You shall give life to the dead.' Said He, 'do you not believe.' Submitted he, 'why not, but I like that my heart may be at rest.