The Torah states "and you shall circumcise him; then he shall eat of it," establishing circumcision as a prerequisite for eating the Passover sacrifice. The Mekhilta uses this verse to address a surprisingly practical medical question: what happens if someone was properly circumcised, but the foreskin grew back and covered the corona?
The ruling is clear and generous. Even if the flesh returned and re-covered the circumcision site, this does not prevent the person from eating the Pesach (Passover) offering or from consuming terumah (the priestly portion of food). The mitzvah of circumcision was fulfilled at the time it was performed. A subsequent physical change does not retroactively invalidate it.
The rabbis in the city of Lod (Lydda) convened and took a formal consensus on a related principle. They ruled that in matters of terumah, this regrowth does not constitute a chatzitzah — a legal "interposition" or barrier that would disqualify someone from a ritual status they had already achieved.
This teaching demonstrates a core principle in rabbinic law: a mitzvah properly performed at the right time retains its validity regardless of what happens afterward. The body may change, circumstances may shift, but the spiritual reality created by a genuine act of covenant-making endures. The rabbis refused to let biology overrule the permanence of a sacred commitment once sincerely undertaken.