Reference for Chagigah 17:15

והאמר חזקיה נטמא ביום מביא בלילה אינו מביא

But Chizkiya said, [A Nazirite,] if [further] made ritually impure on the [eighth] day, brings an [additional offering], but [if he became ritually impure] in the [previous] night, does not bring it.

Jastrow