God grants a second miraculous sign, transforming a healthy hand into a diseased one and back again. This act goes beyond a simple display of divine power, carrying layers of moral instruction, historical symbolism, and personal guidance for a new leader.
When directing this action, God speaks with a soft and considerate tone, using a term of request. Since experiencing a diseased hand is deeply unpleasant, God approaches the matter gently [רש״ר הירש]. He instructs Moses to place his hand into his bosom, generally understood as under his garment near his chest [אבן עזרא, שטיינזלץ], or perhaps specifically in the armpit [אבן עזרא]. This placement ensures the transformation happens in secret rather than out in the open. There is a profound principle at work here: wonders and blessings naturally rest upon things that are hidden from the public eye. This hiddenness mirrors Moses' own personal journey. God had distanced him from Egypt, sending him to the desert of Midian. There, far away from public attention, he underwent a quiet, unseen transformation to become an elevated spiritual figure and the future leader of Israel [העמק דבר].
Upon removing his hand, it is afflicted with leprosy as white as snow. While this illness is typically white, the comparison to snow points to an exceptionally severe and incurable form of the disease, which only magnifies the scale of the miracle [שד״ל]. This transformation is not a mere optical illusion or a trick of the mind. It is a complete physical reality, rendering the hand entirely impure in both a physical and legal sense [צפנת פענח].
The specific choice of this disease carries several complementary meanings. The primary approach among commentators views it as a direct punishment and an educational lesson. The disease is a consequence of speaking poorly of others, specifically because Moses doubted the Israelites and claimed they would not believe him. The snow-white appearance serves as proof that the affliction is a specific penalty for negative speech rather than a punishment for arrogance, much like the illness that later struck the prophetess Miriam [רש״י, משכיל לדוד]. This perspective leads to a chronological question: if the disease was a punishment for his doubt, it seemingly should have been presented as the very first sign rather than the second [אבן עזרא].
Alternatively, the event serves as a moral and philosophical parable. Folding one's hand into the bosom represents laziness, weakness, and an avoidance of action. God is showing that when a person refuses to actively build the world and instead hides his hands away, those hands become diseased. Such a condition represents a state of idleness, destruction, and death [מלבי״ם]. From another perspective, the sign acts as a historical symbol for the journey of the Israelites. The hand itself represents the nation. Initially, they were healthy and free. Then, God allowed them to be struck with the painful affliction of Egyptian slavery. Ultimately, however, He will heal them and restore them to their original state of freedom [אבן עזרא].