Parashas Naso · Passuk 6:10
On the eighth day they shall bring two turtledoves or two pigeons to the priest, at the entrance of the Tent of Meeting.
Chabad.org — English translation + Rashi
Source: Nazir 44b.
English: “And on the eighth day” — “eighth” is said here and “eighth” is said elsewhere; just as there the eighth day and onward is valid, so here.
In context: The gezerah shavah aligns the timing of the nazir’s bird-offerings after impurity with other eighth-day sacrificial rules.
Custom
Chazal apply the eighth-day standard from parallel verses to the nazir’s post-impurity offerings.