20:22
“Now draw thy hand close to thy side: It shall come forth white (and shining), without harm(or stain),- as another Sign,-
Commentators explain that the second of the great miracles granted to Moses was the sign of the “white” or shining hand. Under normal circumstances, a whitening of the skin might indicate disease, such as leprosy or another undesirable condition. In this case, however, the transformation of Moses’ hand was not associated with illness. Instead, it appeared radiant and luminous, reflecting a form of divine light. As such, the event was presented as a genuine miracle granted by God, far beyond the abilities of Egyptian magicians or any form of human magic (Ali, n.d.).
References:
Yusuf Ali, Abdullah. Translation and Commentary of the Quran. (surah 20 verse 22).