Mekhilta d'Rabbi Yishmael 0.1.12

(Exodus 12:25) "And it shall be, when you come to the land": The service is contingent upon their entering the land and thereafter. (In the desert they were obliged to observe only one Pesach, in the second year, by Divine command.) "as He has spoken":

And where did He speak it? (Ibid. 6:8) "and I shall bring you to the land, etc."

Similarly, (Ibid. 16:23) "This is what the L–rd has spoken: 'A resting, a holy Sabbath, etc.'" And where did He speak it? (Ibid. 5) "And it shall be on the sixth day that they shall prepare, etc."

Similarly, (Leviticus 10:3) "This is as the L–rd spoke: With My near ones I will be sanctified." And where did He speak it? (Exodus 29:43) "And I will be appointed there for the children of Israel and it (the mishkan) will be sanctified by My glory" (i.e., by My glorifiers).

Similarly, (Devarim 11:25) "The L–rd your G–d will put the dread and fear of you over the whole land … as He spoke to you." And where did He speak it? (Exodus 23:27) "My fright shall I send before you, and I shall confound all the people, etc."

(Devarim 12:20) "When the L–rd your G–d broadens your boundary, as he spoke to you, etc." And where did He speak it? (Exodus 34:24) "for I shall drive out nations from before you and I shall broaden your boundary," (Ibid. 23:31) "And I shall set your boundary from the Red Sea, etc."

Similarly, (Devarim 15:6) "for the L–rd your G–d will bless you as He spoke to you." And where did He speak it? (Ibid. 7:14) "Blessed shall you be over all other peoples."

Similarly (Ibid. 26:18) "and the L–rd has affirmed this day to make you His chosen people as He spoke to you." And where did He speak it? (Exodus 19:5) "then you shall be to Me chosen above all the peoples."

Similarly (Devarim 26:19) "and to place you higher than all the nations … as He spoke." And whence did He speak it? (Ibid. 28:13) "And the L–rd will make you the head, and not the tail.

Similarly, (Isaiah 1:2) "Hear, O heavens, and give ear, O earth, as the L–rd has spoken." And where did He speak it? (Devarim 32:1) "Hear, O heavens, and I shall speak."

Similarly, (Isaiah 40:5) "The glory of the L–rd shall appear, and all flesh will behold as one, for the mouth of the L–rd has spoken." And where did He speak it? (Devarim 32:39) "See, now, that I — I am He, and there is no god beside Me."

Similarly, (Isaiah 1:19-20) "If you acquiesce and pay heed, the good of the earth will you eat. But if you refuse and rebel, the sword will devour you; for the mouth of the L–rd has spoken." And where did He speak it? (Leviticus 26:25) "… I will bring against you an avenging sword, etc."

Similarly, (Isaiah 25:8) "He will destroy death forever … for the L–rd has spoken." And where did He speak it? (Devarim 32:39) "I put to death and I bring to life, etc."

Similarly, (Isaiah 58:14) "then you will rejoice in the L–rd, and I will 'ride' you on the heights of the earth, etc." And where did He speak it? (Devarim 32:13) "He will 'ride' him on the heights of the earth, etc."

Similarly, (Ezekiel 39:8) "Behold, it has come; it has arrived, says the L–rd G–d. This is the day of which I spoke." And where did He speak of it? (Devarim 32:42) "I will make My arrows drunk with blood, etc."

Similarly, (Michah 4:4) "and each man will sit under his grapevine … for the mouth of the L–rd of hosts has spoken." And where did He speak it? (Leviticus 26:6) "And I will place peace in the land, etc."

Similarly, (Ovadiah 1:18) "And there will be no survivor of the house of Esav, for the mouth of the L–rd has spoken." And where did He speak it? (Numbers 24:18-19) "And Edom (Esav) will become an inheritance … and a victor will issue from Jacob and will destroy all trace of Ir."

Similarly, (Genesis 21:1) "And the L–rd remembered Sarah (for motherhood) as He had said." "And where did He say it? (Ibid. 17:19) "And G–d said: But Sarah your wife will bear, etc."

Similarly, (Ibid. 21:1) "And the L–rd did for Sarah as He had spoken." And where did He speak it? (Ibid. 15:4) "And the 'speaking' of the L–rd was to him. This one (Ishmail) will not inherit you, etc."

Similarly, (Yoel 4:8) "and I will sell your sons and your daughters, etc." And where did he speak it? (Genesis 9:25) "And he (Noach) said: Cursed is Canaan. A servant of servants will he be to his brothers."

Similarly, (Devarim 17:16) "And the L–rd said to you: You will not go back this way (to Egypt) again." And where did He say it? (Exodus 14:13) "For your seeing Egypt is (only) this day. You will see them no more forever."

Similarly, (Isaiah 65:25) "The wolf and the lamb will graze together…said the L–rd." And where did He say it? (Leviticus 26:6) "I will cut off wild beasts from the land."

Similarly, (I Kings 11:2) "… of the nations of which the L–rd said … You shall not come among them, etc." And where did He say it? (Devarim 7:3) "And you shall not intermarry with them, etc."

Similarly, (Malachi 3:17) "'and they will be Mine,' said the L–rd." And where did He say it? (Exodus 19:5) "And you will be unto Me, chosen, etc."

Similarly, (Yoel 3:5) "And all who call in the name of the L–rd … as the L–rd said." And where did He say it? (Devarim 28:10) "And all the peoples of the earth will see that the L–rd's name is called upon you, etc."

Similarly, (Isaiah 66:20-21) "And they will bring all your brothers from all the nations as an offering to the L–rd … And also from them will I take Cohanim and Levites, the L–rd said." And where did He say this? (Devarim 29:28) "What is concealed (from us [e.g., who is a Cohein and who, a Levite]) is known to the L–rd our G–d."

Here, too, (Exodus 12:25) "And it shall be, when you come to the land that the L–rd will give you, as He has spoken, etc." And where did He speak it? (Ibid. 6:8) "And I shall bring you to the land, etc."

(Exodus 12:26) "And it shall be, when your sons say to you, etc.": At that time, Israel was receiving bad tidings, that the Torah was destined to be forgotten. Others say they were receiving good tidings, that they were destined to see sons and sons of sons. (Exodus 12:27) "And the people bowed down and prostrated themselves": Why did they bow down? For it is written (Ibid. 13:18) "And the children of Israel went out of Egypt chamushim" — one out of five ("chamishah"). Others say one out of fifty ("chamishim"). And others say one out of five hundred ("chamesh me'oth").

R. Nehorai says; Upon my oath, not one in five hundred went out. For it is written (Ezekiel 16:7) "Numerous as the spouts of the field did I make you" (in Egypt), and (Exodus 1:7) "And the children of Israel were fruitful, and teemed" — One woman would bear six in one womb. And you say one in five hundred went out? And when did they die? In the three days of darkness, of which it is written (Exodus 10:23) "One man could not see another." The Jews buried their dead, and they were thankful and praised (the L–rd) that their foes could not see (the dead) and rejoice in their downfall.

(Ibid. 12:27) "Then you shall say that it is a Paschal sacrifice to the L–rd.": R. Yossi Haglili said: The Jews would have deserved to die in Egypt (if not for the merit of the Paschal sacrifice) whereby the last of them consummated his sacrifice (and lived.) "Then you shall say that it is a Paschal sacrifice." We are hereby apprised that all who hear of or see the miracles that the Holy One Blessed be He wrought in Egypt must give praise. And thus is it written (Exodus 18:8-9) "And Moses related to his father-in-law all that the L–rd did to Pharaoh and to Egypt. And Yithro rejoiced, etc."

(Ibid. 28) "And the children of Israel went and they did": Reward is given for both the going and the doing.

"and they did": Now did they already do? — Their taking it upon themselves to do is regarded as their doing. "as the L–rd commanded": We are hereby apprised of their eminence. Exactly as Moses and Aaron commanded them thus did they do.

What is the intent of (the seemingly superfluous) "Thus did they do"? Moses and Aaron, too, did thus.