1,094. Chometz on Erev Pesach

Chometz u’Matzah 1:9

The Sages prohibited eating chometz starting from the beginning of the sixth halachic hour in order to distance people from the possibility of violating the Biblical prohibition. Accordingly, it is rabbinically prohibited to eat or to benefit from chometz from the start of the sixth hour. From the seventh hour on, eating chometz is Biblically prohibited. We do not eat chometz during the fifth halachic hour of the day out of concern that it may be cloudy and one may be unable to distinguish between the fifth and sixth hours. One is still permitted to derive benefit from chometz during the fifth hour. Terumah and the loaves of thanksgiving offerings, which are chometz, are held in abeyance during the fifth hour because of their holiness; they are not eaten but they are likewise not burned until the start of the sixth hour. At that time, they are entirely burned.

Chometz u’Matzah 1:10

We see that it is permitted to eat chometz on 14 Nisan until the end of the fourth halachic hour. During the fifth hour, chometz may not be eaten but benefit may be derived from it. One who eats chometz in the sixth hour is liable to stripes for acting rebelliously, while one who eats chometz in the seventh hour is liable to lashes.