Rashi on Deuteronomy 16:3/רש"י על דברים ט״ז:ג׳

1לחם עני THE BREAD OF AFFLICTION — i.e. bread that calls to mind the affliction to which they were subjected in Egypt (Sifrei Devarim 130:5).

2כי בחפזון יצאת FOR THOU CAMEST FORTH [FROM THE LAND OF EGYPT] IN HASTE, and the dough therefore had no time to become leavened, and this (the eating of unleavened bread) shall be unto you as reminder of this. The haste, spoken of here, was not on thy part, but on Egypt’s part, for so it states, (Exodus 12:33) “And Egypt was urgent upon the people [hastening to send them out of the land]” (Sifrei Devarim 130:6; cf. Berakhot 9a).

3למען תזכר THAT THOU MAYEST REMEMBER through the eating of the Passover sacrifice and the unleavened bread, את יום צאתך THE DAY WHEN THOU CAMEST FORTH [OUT OF THE LAND OF EGYPT].