Midras Mazmur 116:13: Otzar Midrashim, Shemot Rabbah, Mekhilta DeRabbi Yishmael & Midrash Tanchuma

In the future to come, the Holy Blessed One will reveal the Torah’s reasoning to Israel. Why the prohibition on marrying two sisters? Why milk and meat? Why swineflesh? Why mixed crops? After He reveals to them the Torah’s reasoning, He will say to the righteous, “Enter the Garden of Eden and eat a feast prepared for you, and drink wine preserved from grapes from the six days of creation!” They say before Him, “Master of the universe! There is no party where the host isn’t found within! But if you want, let Your presence be among us!” Immediately David says before the Holy Blessed One, “Master of the universe! Do good with us and sit with us!” At that time the Holy Blessed One listens to David, as it is said, “Then you will call and the LORD will answer, you will cry out and He will say ‘Here I am!’” (Isaiah 58:9) Immediately, the Holy Blessed One enters with David and all the righteous standing at their seats, and the the Holy Blessed One sits on His glorious throne, and David sits corresponding to Him on a throne prepared for him, as it is said, “And his throne like the sun beside Me.” (Psalm 89:37) And all the righteous sit on their chairs and eat and rejoice and drink around three cups of pressed wine, as it is said, “I will have you drink of the spiced wine, of the juice of my pomegranate.” (Song of Songs 8:2) ^{Alternative reading} Alternative reading: "And Gabriel lifts two chairs, one for the Holy Blessed One and one for David, as it is said, 'And his throne like the sun beside Me.' And they eat and drink three cups..." See Tanna d'Vei Eliyahu Zutta, chapter 20. And they mix for them the cup of blessing, and the cup of blessing is two hundred and twenty-one log, as it is said, “You will set a table before me facing my enemies; You rubbed my head with oil; my cup overflows.” (Psalm 23:5) “Overflows” in gematria is thus. After they eat, someone says, “Who will bless?” Someone says to Abraham, “You, take it up and bless, for you are the father of the universe!” He says to them, “I cannot bless, for from me came a seed that would aggrieve the Holy Blessed One!” Someone says to Isaac, “You, take it up and bless, for you were bound upon the back of the altar!” He says to them, “I cannot bless, for from me came a seed that would destroy the Holy Blessed One’s house!” Someone says to Jacob, “You, take it up and bless, for your bed was complete before the Present One!” He says to them, “I cannot bless, for I married two sisters in their lives, which the Torah would later forbid!” As it is said, “And a woman with her sister you will not take as wife to stress." (Leviticus 18:18) Someone says to Moses, “You, take it up and bless, for you received the Torah and upheld it!” He says to them, “I cannot bless, for I did not merit to enter the land of Israel.” Someone says to Joshua, “You, take it up and bless, for you brought Israel into the land and upheld the Torah!” He says to them, “I cannot bless, for I did not merit a son.” Someone says to David, “You, take it up and bless, for you are the sweet singer of Israel, (II Samuel 23:1) and their prince! As it is said, “And David My servant is their prince for eternity.” (Ezekiel 37:25) And he says, “I will bless, and it is fitting for me to bless!” As it is said, ‘The cup of salvation I will raise and on the name of the LORD I will call." (Psalm 116:13) After they eat and drink and bless, the Holy Blessed One brings out the Torah and lays it on His lap and studies from it about impurity and purity, about prohibitions and permissions, laws and legends, and David says songs before the Holy Blessed One and the righteous respond after him, "Amen! May His great name be blessed for eternity and eternity of eternities! Blessed be!" from the Garden of Eden, and the sinners of Israel respond “Amen!” from the midst of hell. Immediately the Holy Blessed One says to the messenger-angels, “Who are those who respond ‘Amen!’ from the midst of hell?” One says before Them, “Master of the universe! These sinners of Israel, who despite their great stress, strengthen themselves and say ‘Amen!’ before You.” Immediately the Holy Blessed One says to the messenger-angels, “Open for them the gates of the Garden of Eden, and they will come and hymn before Me!” As it is said, “Open the gates so the righteous nation comes, the faith-keeping.” (Isaiah 26:2) Don’t say “the faith-keeping” (shomer emunim) but rather “those who say amens” (she-omrim amenim).

“I appeared to Abraham” – The Holy One blessed be He said to Moses: ‘Alas for those who are lost and are not present.¹³An expression of loss over the deceased. Many times I have revealed Myself to Abraham, Isaac, and Jacob as God Almighty, but I did not make known to them that My name is the Lord as I made known to you, yet they did not question My ways. I said to Abraham: “Arise, walk through the length and the breath of the land…” (Genesis 13:17). He sought to bury Sarah and did not find a place until he purchased it, and he did not question My ways. I said to Isaac: “Reside in this land… [for I will give all these lands] to you and your descendants…” (Genesis 26:3). He sought to drink water but did not find, but rather, “the shepherds of Gerar quarreled with Isaac's shepherds, [saying: The water is ours…]” (Genesis 26:20) and he did not question My ways. I said to Jacob: “The land on which you lie [I will give to you and to your descendants]” (Genesis 28:13). He sought a place to pitch his tent but did not find until he purchased one for one hundred kesita, and he did not question my ways, and did not ask Me what My name is, as you asked.’
‘But you, at the beginning of [receiving] My mission you said to Me: What is Your name? In the end, you said: “Since I came to Pharaoh [to speak in Your name, he has harmed this people, and You did not deliver Your people]” (Exodus 5:23). Regarding that, it is stated: “I have also established My covenant…[to give them the land of Canaan…]” (Exodus 6:4), that it was given to them, as I said to them that I would give the land to them, and they did not question Me. “Moreover, I have heard the cry of the children of Israel” (Exodus 6:5) – because they did not question Me, even though Israel in that generation were not conducting themselves properly, I heard their cry because of the covenant that I had established with their ancestors.’ That is what is written: “And I have remembered My covenant” (Exodus 6:5).
“Therefore say to the children of Israel: I am the Lord, and I will take you out from under the burdens of the Egyptians, and I will deliver you from their labor, and I will redeem you with an outstretched arm, and with great judgments. And I will take you to Me as a people, and I will be to you a God; and you shall know that I am the Lord your God, who brings you out from under the burdens of Egypt ” (Exodus 6:6-7).
“Therefore [lakhen] say to the children of Israel” – lakhen is nothing other than the language of oath-taking, as it is stated: “Therefore [velakhen] I took an oath to the house of Eli” (I Samuel 3:14). The Holy One blessed be He took an oath that He would redeem them, so that Moses would not fear that perhaps the attribute of justice would delay their redemption.
“I will take you out from under the burdens of the Egyptians…” There are four redemptions here: “I will take out…I will deliver…I will redeem…I will take,” corresponding to the four decrees that Pharaoh decreed against them.¹⁴See Shemot Rabba 1:12. The four decrees are: 1) Hard labor to build the storehouse cities, 2) Killing the newborn males, 3) Casting the newborn sons into the Nile, 4) Withholding straw from brick production. Corresponding to them, the Sages instituted four cups on Passover eve, to fulfill what is stated: “I will raise the cup of salvation and call upon the name of God” (Psalms 116:13).
“And I will bring you into the land about which I raised my hand, to give it to Abraham, to Isaac, and to Jacob; and I will give it to you as a heritage; I am the Lord” (Exodus 6:8).
“And I will bring you into the land about which I raised my hand.” I will do for them what I said to your ancestors – that I would give them the Land, and they would inherit it by their [the forefathers] merit.

R. Akiva says: "You shall not do (i.e., deport yourselves) with Me" as others do with their gods. When good befalls them, they honor their gods, viz. (Habakkuk 1:16) "Therefore, he sacrifices to his "nets" (i.e., to his idols, which "net" him riches). And when evil befalls them, they curse their gods, viz. (Isaiah 8:21) "… and he will curse his king and his gods." But, as for you, if I bring good upon you, you give thanks, and when I bring afflictions upon you, you give thanks. And thus did David say (Psalms 116:3) "the cup of salvation shall I raise, and in the name of the L-td will I call" — (Ibid. 4) "Trouble and sorrow will I find, and in the name of the L–rd shall I call." And thus, Iyyov says (Iyyov 1:21) "the L–rd has given and the L–rd has taken — Let the name of the L–rd be blessed!" Both for the good and for the evil. What does his wife say to him? (Ibid. 2:9) "Do you still hold on to your innocence? Blaspheme G–d and die!" He answers (Ibid. 10) "You speak as one of the lowly ones!