Exodus 12:8
And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it.
Torrey's Topical Textbook—AKJV

Numbers 9:11
The fourteenth day of the second month at even they shall keep it, and eat it with unleavened bread and bitter herbs.
Torrey's Topical Textbook—AKJV