Exodus 12:5

5.Your lamb shall be without blemish. We shall see elsewhere, that in all their sacrifices prescribed by the Law they were diligently to beware, lest there should be any spot or fault in them; and by this the people were reminded, that the expiation was not legitimate, unless it possessed the utmost perfection, such as is never to be found in men. It is not to be wondered, therefore, that God should now require the Passover to be of one year old, and without blemish, that the Israelites might know that in order to propitiate God, a more excellent price was required than could be discovered in the whole human race; and since such excellency could much less exist in a beast, the celestial perfection and purity of Christ was shewn forth by this visible perfection of the lamb, or kid. It was with reference to this also that; they were commanded to keep it up separate from the rest; of the flock, from the tenth until the fourteenth day of the month. As to God’s will, that the side-posts and lintel should be sprinkled with blood, by this sign He plainly taught them, that the sacrifice would profit none but those who were stained and marked with Christ’s blood; for this sprinkling was equivalent to their bearing each one the mark: of His blood upon their forehead. And, in effect, Christ, by the outpouring of His blood, has not delivered all, but only the faithful, who sanctify themselves with it. That internal sprinkling indeed holds the first place, which Peter teaches us to be effected by the power of the Spirit, (1 Peter 1:2;) yet by this external sign the Israelites were instructed that they could not be protected from God’s wrath, except by holding up against it the shield of the blood. And this corresponds with the lesson learnt above, that the same universal sacrifice was offered particularly in every house, in order that thus its peculiar instruction might affect them more seriously, when generally it would have been uninteresting and ineffectual. I prefer to be ignorant as to why He required the flesh to be roasted and not boiled, rather than to invent such unfounded subtleties, as that Christ was, in a manner, roasted on the Cross. A nearer approach to the truth appears to me to be, that God desired thus to mark their haste, because, when their implements were all packed up, the meat would be more easily roasted on a spit than cooked in the pot. And this also is the tendency of the precept respecting the manner of eating it, in which three things are to be observed, the unleavened bread, the sauce of bitter herbs, and the girded loins, together with the rest of the costume of travelers. Undoubtedly God commanded the bread to be made without leaven on account of their sudden departure, because He would snatch his people out of Egypt, as it were, in a moment; and, therefore, they baked unleavened loaves out of flour hurriedly kneaded. (315) It was required that the remembrance of this should be renewed every year, in order that their posterity might know that their deliverance was afforded them from above, since their fathers hastily took flight without having made any preparation for their journey; for any greater preparation would have thrown some shade upon the divine grace, which shone forth more brightly on account of their want of food. God would have them content with bitter herbs, because hasty travelers, and especially in an enemy’s country, are satisfied without delicacies, and whatever sauce they meet with is very grateful to their taste, nor does its bitterness seem offensive to them, as it does in seasons of abundance and ease. Possibly too they were reminded of their former condition; for under so dire and bitter a tyranny nothing could be sweet or pleasant. But their haste was still more plainly represented by their eating the lamb hurriedly with their shoes on their feet, and their loins girded, and leaning on their staves. Men pass from their suppers to bed and to repose; and therefore the ancients used both to take off their shoes and to lie down to it; but the people’s necessity inverts this order, since they were compelled to fly immediately from their supper. And hence the reason is subjoined, “it is the Lord’s passover;” since they escaped in safety amidst the confusion, and when the sword of God was raging. We must, however, bear in mind what we have already said, that the use of this sacrament was twofold, both to exercise the people in the recollection of their past deliverance, and to nourish in them the hope of future redemption; and therefore the passover not only reminded them of what God had already done for His people, but also of what they were hereafter to expect from Him. Consequently there is no doubt that the Israelites ought to have learnt from this rite that they were redeemed from the tyranny of Egypt on these terms, viz, that a much more excellent salvation still awaited them. But this spiritual mystery was more clearly laid open by the coming of Christ; and therefore Paul, accommodating this, ancient figure to us, commands us, because

“Christ our passover is sacrificed for us,” to “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 5:7.)

God therefore formerly wished the houses, in which the Passover was celebrated, to be free from all corruption; and far more does it become us now to take care of this, lest the sacrifice wherewith Christ has redeemed us from eternal death, should be polluted by any leaven of wickedness. To the same effect (316) is what follows, warning us lest we should be devoted to the attractions of the world, and lest our course should be delayed by the enticements of pleasure; but that we are pilgrims on earth, and should be ever girt and ready to make haste; and that although the cross of Christ be bitter, yet we should not refuse to taste it.