They shall eat the flesh - roast with fire - As it was the ordinary custom of the Jews to boil their flesh, some think that the command given here was in opposition to the custom of the Egyptians, who ate raw flesh in honor of Osiris. The Ethiopians are to this day remarkable for eating raw flesh, as is the case with most savage nations.

Unleavened bread - מצות matstsoth, from מצה matsah, to squeeze or compress, because the bread prepared without leaven or yeast was generally compressed, sad or heavy, as we term it. The word here properly signifies unleavened cakes; the word for leaven in Hebrew is חמץ chamets, which simply signifies to ferment. It is supposed that leaven was forbidden on this and other occasions, that the bread being less agreeable to the taste, it might be emblematical of their bondage and bitter servitude, as this seems to have been one design of the bitter herbs which were commanded to be used on this occasion; but this certainly was not the sole design of the prohibition: leaven itself is a species of corruption, being produced by fermentation, which in such cases tends to putrefaction. In this very light St. Paul considers the subject in this place; hence, alluding to the passover as a type of Christ, he says: Purge out therefore the old leaven - for Christ our passover is sacrificed for us: therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth; 1 Corinthians 5:6-8.

Bitter herbs - What kind of herbs or salad is intended by the word מררים merorim, which literally signifies bitters, is not well known. The Jews think chicory, wild lettuce, horehound, and the like are intended. Whatever may be implied under the term, whether bitter herbs or bitter ingredients in general, it was designed to put them in mind of their bitter and severe bondage in the land of Egypt, from which God was now about to deliver them.

eat the

Matthew 26:26 And as they were eating, Jesus took bread, and blessed it, and broke it, and gave it to the disciples, and said, Take...

John 6:52-57 The Jews therefore strove among themselves, saying, How can this man give us his flesh to eat...

roast

Deuteronomy 16:7 And you shall roast and eat it in the place which the LORD your God shall choose: and you shall turn in the morning...

Psalm 22:14 I am poured out like water, and all my bones are out of joint: my heart is like wax; it is melted in the middle of my bowels.

Isaiah 53:10 Yet it pleased the LORD to bruise him; he has put him to grief: when you shall make his soul an offering for sin, he shall see his seed...

unleavened

Exodus 13:3,7 And Moses said to the people, Remember this day, in which you came out from Egypt, out of the house of bondage...

Exodus 34:25 You shall not offer the blood of my sacrifice with leaven...

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.

Deuteronomy 16:3 You shall eat no leavened bread with it; seven days shall you eat unleavened bread therewith, even the bread of affliction...

Amos 4:5 And offer a sacrifice of thanksgiving with leaven, and proclaim and publish the free offerings: for this likes you...

Matthew 16:12 Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees...

1 Corinthians 5:6-8 Your glorying is not good. Know you not that a little leaven leavens the whole lump...

Galatians 5:9 A little leaven leavens the whole lump.

with bitter

Exodus 1:14 And they made their lives bitter with hard bondage, in mortar, and in brick, and in all manner of service in the field...

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.

Zechariah 12:10 And I will pour on the house of David, and on the inhabitants of Jerusalem, the spirit of grace and of supplications...

1 Thessalonians 1:6 And you became followers of us, and of the Lord, having received the word in much affliction, with joy of the Holy Ghost.

The Blood
Now, at the time of which this Book of Exodus speaks, Egypt was exposed to a terrible peril. Jehovah himself was about to march through the streets of all the cities of Egypt. It was not merely a destroying angel, but Jehovah himself; for thus it is written, "I will pass through the land of Egypt this night, and will smite all the first-born in the land of Egypt, both man and beast." No one less than I AM, the great God, had vowed to "cut Rahab" with the sword of vengeance. Tremble, ye inhabitants …
Charles Haddon Spurgeon—Spurgeon's Sermons Volume 5: 1859

Appendix xii. The Baptism of Proselytes
ONLY those who have made study of it can have any idea how large, and sometimes bewildering, is the literature on the subject of Jewish Proselytes and their Baptism. Our present remarks will be confined to the Baptism of Proselytes. 1. Generally, as regards proselytes (Gerim) we have to distinguish between the Ger ha-Shaar (proselyte of the gate) and Ger Toshabh (sojourner,' settled among Israel), and again the Ger hatstsedeq (proselyte of righteousness) and Ger habberith (proselyte of the covenant). …
Alfred Edersheim—The Life and Times of Jesus the Messiah

Hope for the Heathen
Throughout his ministry Isaiah bore a plain testimony concerning God's purpose for the heathen. Other prophets had made mention of the divine plan, but their language was not always understood. To Isaiah it was given to make very plain to Judah the truth that among the Israel of God were to be numbered many who were not descendants of Abraham after the flesh. This teaching was not in harmony with the theology of his age, yet he fearlessly proclaimed the messages given him of God and brought hope …
Ellen Gould White—The Story of Prophets and Kings