And this day shall be unto you for a memorial; and ye shall keep it a feast to the LORD throughout your generations; ye shall keep it a feast by an ordinance for ever. A memorial - To keep up a remembrance of the severity and goodness, or justice and mercy, of God. Ye shall keep it a feast - it shall be annually observed, and shall be celebrated with solemn religious joy, throughout your generations - as long as ye continue to be a distinct people; an ordinance - a Divine appointment, an institution of God himself, neither to be altered nor set aside by any human authority.
For ever - חקת עולם chukkath olam, an everlasting or endless statute, because representative of the Lamb of God who taketh away the sin of the world; whose mediation, in consequence of his sacrifice, shall endure while time itself lasts; and to whose merits and efficacy the salvation of the soul shall be ascribable throughout eternity. This, therefore, is a statute and ordinance that can have no end, either in this world or in the world to come. It is remarkable that though the Jews have ceased from the whole of their sacrificial system, so that sacrifices are no longer offered by them in any part of the world, yet they all, in all their generations and in all countries, keep up the remembrance of the passover, and observe the feast of unleavened bread. But no lamb is sacrificed. Their sacrifices have all totally ceased, ever since the destruction of Jerusalem by the Romans. Even the flesh that is used on this occasion is partly roasted and partly boiled, that it may not even resemble the primitive sacrifice; for they deem it unlawful to sacrifice out of Jerusalem. The truth is, the true Lamb of God that taketh away the sin of the world has been offered, and they have no power to restore the ancient type. See Clarke on Exodus 12:27 (note).