Bais HaVaad on the Parsha, Parshas Shemos
Excerpted and adapted from a shiur by Dayan Yosef Greenwald
Shall I go and call you a wet nurse from among the Ivri women, that she might nurse the child for you?
Because she brought him to many Egyptian women and he didn’t nurse, because he was destined to speak with the Shechinah.
Why is a child subject to food prohibitions? The Gemara says in Yevamos that forbidden foods are metamtem es haleiv(create a spiritual blockage in the heart). This applies even to children; though not yet subject to the prohibition, they still suffer the effects.
What in a gentile mother’s milk causes timtum haleiv? Some say that the milk is kosher, but because it transmits the nutrients from the nonkosher food the mother ate, it causes spiritual impediment. Others explain that milk transmits to the child the essence of the woman who produced it, so if it comes from an impure source, it will impact the baby negatively.
The Rishonim point out that the food you consume becomes a part of your body. The capacity of your body to be a receptacle for devarim shebikdusha can be damaged with forbidden food more than with any other kind of violation.
It is interesting to note that ma’achalos asuros differs from some other aveiros. In the case of Shabbos, when a pikuach nefesh situation requires that Shabbos be violated, there is no negative impact. By contrast, there are authorities who say that one who eats ma’achalos asuros because he is required to do so for pikuach nefesh still incurs the effects of timtum haleiv.