Dalil

Quran Taha 20:22

وَٱضۡمُمۡ يَدَكَ إِلَىٰ جَنَاحِكَ تَخۡرُجۡ بَيۡضَآءَ مِنۡ غَيۡرِ سُوٓءٍ ءَايَةً أُخۡرَىٰ

Translation

And draw in your hand to your side; it will come out white without disease - another sign,