1.- What is a Covenant?

Between God and Man, a solemn oath followed by signs and sacrifices. This relationship is sealed with promises of blessing when fulfilled and curses when broken.

“And he believed in the Lord, and He accounted it to him for righteousness.”   Genesis 15:6

2.- Can a Covenant be Generational?

Yes, the Covenant of Abraham is a covenant for all Israel, and it is still active. A new covenant does not eliminate the previous one.

“Brethren, I speak in the manner of men: Though it is only a man’s covenant, yet if it is confirmed, no one annuls or adds to it. 16 Now to Abraham and his Seed were the promises made. He does not say, “And to seeds,” as of many, but as of one, “And to your Seed,”[a] who is Christ. 17 And this I say, that the law, which was four hundred and thirty years later, cannot annul the covenant that was confirmed before by God in Christ,[b] that it should make the promise of no effect.  Galatians 3:15-17

3.- Do they talk about the New Covenant in the Old Testament? 

Yes, the Scriptures about the New Covenant are in Jeremiah, Ezekiel and other places in the Tanak (Hebrew Bible)

“Behold, the days are coming, says the Lord, when I will make a new covenant with the house of Israel and with the house of Judah— 32 not according to the covenant that I made with their fathers in the day that I took them by the hand to lead them out of the land of Egypt, My covenant which they broke, though I was a husband to them,[a] says the Lord. 33 But this is the covenant that I will make with the house of Israel after those days, says the Lord: I will put My law in their minds, and write it on their hearts; and I will be their God, and they shall be My people. 34 No more shall every man teach his neighbor, and every man his brother, saying, ‘Know the Lord,’ for they all shall know Me, from the least of them to the greatest of them, says the Lord. For I will forgive their iniquity, and their sin I will remember no more.”          Jeremiah 31:31-34

For I will take you from among the nations, gather you out of all countries, and bring you into your own land. 25 Then I will sprinkle clean water on you, and you shall be clean; I will cleanse you from all your filthiness and from all your idols. 26 I will give you a new heart and put a new spirit within you; I will take the heart of stone out of your flesh and give you a heart of flesh. 27 I will put My Spirit within you and cause you to walk in My statutes, and you will keep My judgments and do them. 28 Then you shall dwell in the land that I gave to your fathers; you shall be My people, and I will be your God.”  Ezekiel 36:24-28

4.- What is the seal of the New Covenant?

The Holy Spirit

“who also has sealed us and given us the Spirit in our hearts as a guarantee.”   2 Corinthians 1:22

 “In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise, 14 who[a] is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory.”    Ephesians 1:13-14

5.- What sacrifice confirms the New Covenant? 

The death and resurrection of the Messiah and Lord Jesus Christ

“Therefore He who supplies the Spirit to you and works miracles among you, does He do it by the works of the law, or by the hearing of faith?— 6 just as Abraham “believed God, and it was accounted to him for righteousness.”[a] 7 Therefore know that only those who are of faith are sons of Abraham.”   Galatians 3:5-7

“that the blessing of Abraham might come upon the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith.”   Galatians 3:14