3 Covenant Groups

Question

Richard Pratt, in his lecture on paedobaptism, says that Jeremiah 31:31ff. ("They shall not teach one another or say to each other, 'Know the Lord'") is part of the new covenant that is not yet fulfilled. How does this square with Hebrews 8:11 where this verse seems to be cited to say that this aspect is already fulfilled in the present?
At the end of your answer Ra, you make this following statement: "Thus, we have biblical proof that the renewed covenant had already been broken by the time Hebrews was written. Moreover, Hebrews itself also teaches us that the renewed covenant can be broken when it tells us of the punishment that will fall upon some who have been "sanctified" by the "blood of the covenant" (Heb. 10:26-31)".
My question is this: Is your answer here based on the idea as Dr. Pratt teaches in his "He Gave Us Prophets" video lectures that in the OT economy there was the visible covenant community, the invisible, and then those outside of the community without hope at all. Therefore implying that those who have broken the new covenant were only ever part of the visible community. Going further, I notice in Ephesians 2:11ff Paul speaks of those who were once cut off from the covenants which strikes me as NT elaboration on this OT idea of this 3rd community without hope. So my question then becomes: Is there still this 3rd community today who are cutoff from the covenant and without hope in the world?

Answer

Yes, in the New Testament we also have three communities, just like in the Old Testament. Those who break the new covenant were only ever part of the visible community, not the invisible. If we are in the invisible community, we are united to Christ and we thereby receive his status as perfect covenant keepers so that we are never counted as breakers of the new covenant (or never again counted as breakers of the new covenant, as is the case when we are part of the visible community before we are saved.)

And yes, Ephesians 2:11ff. refers to the third community without hope. Specifically, Paul is saying that before Christ came, the Gentiles were not part of God's special covenant community to whom he had given the promises of redemption. But now that Christ has come, Gentiles may enter the church (which has replaced Israel as the faithful covenant community, being the body that now contains the invisible community). By doing so, they enter the visible community. And by doing so in faith, they also enter the invisible community.
Today, the third community is everyone who is not a member of the visible church. The second community is the visible church (all church members), and the first community is the invisible church (believers within the church). Those outside the church have no hope in the world because they cannot be saved. They must come into the church in order to be saved.