The Hand of Musa turning White without any Disease

This is the second sign of Musa. That is Allah has commanded him to place his hand into the opening of his garment, as is clearly stated in another Ayah. It mentioned here merely as a passing reference, saying:

وَاضْمُمْ يَدَكَ إِلَى جَنَاحِكَ

Commentary

When Sayyidna Musa (علیہ السلام) received the high honour of conversing with Allah Ta` ala and was granted the mission of prophethood, then, instead of relying on his own self and on his own ability, he turned to Allah Ta` ala and sought His help in the discharge of his duties without which it would be impossible for him to endure and persevere in the face of the trials and tribulations inherent in the performance of his mission. He, therefore, prayed to Allah Ta` ala to grant him five favours.