Seven days shall ye eat unleavened bread; even the first day ye shall put away leaven out of your houses: for whosoever eateth leavened bread from the first day until the seventh day, that soul shall be cut off from Israel.
Seven days shall ye eat unleavened bread. For the probable reason of the extension of the feast over a week, see the note on "unleavened bread," Exodus 12:8. The Passover being a distinct feast, these seven days were to be reckoned from its celebration.
Even the first day ye shall put away leaven out of your houses, х 'ak (H389) bayowm (H3117) haari'shown (H7223)] - wholly the first day; i:e., the very first day, on no other but the first day (Gesenius).
For whosoever eateth leavened bread from the first day ... This was to commemorate another circumstance in the departure of the Israelites, who were urged to leave so hurriedly that their dough was unleavened (Exodus 12:39), and they had to eat unleavened cakes (Deuteronomy 16:3). The greatest care was always taken by the Jews to free their houses from leaven-the owner searching every corner of his dwelling with a lighted candle. A figurative allusion to this is made, 1 Corinthians 5:7. The exclusion of leaven for seven days would not be attended with inconvenience in the East, where the usual leaven is dough, kept until it becomes sour, and it is kept from one day to another for the purpose of preserving leaven in readiness. Thus, even were there none in all the country, it could be obtained within 24 hours (Harmer).
Cut off - excommunicated from the community and privileges of the chosen people.