Is the New Covenant everlasting? Will we be under the New Covenant in heaven?
Believe it or not, this is a difficult question. Logically, it would seem that if the answer to the first question is yes, then the answer to the second question also needs to be yes, but this is not the case. The answer depends on your definition of “everlasting.” In the Western mind, or, specifically, to the English speaker, the word “everlasting,” which is a synonym of eternal or forever, means for an infinite amount of time. This is not the definition of the Hebrew word which is translated as “everlasting” in most Old Testaments. The most famous passage in the Old Testament which contains the word everlasting is probably Genesis 17:7, which is when God gave the covenant of circumcision. This is the quote: “I will establish my covenant [of circumcision] as an everlasting covenant between me and you and your descendants after you for the generations to come, to be your God and the God of your descendants after you.”
The word translated “everlasting” in this passage is the Hebrew word owlam. To the Western mind, this means forever—for an infinite amount of time. But this is not the Jewish understanding of the word, and it is not the early Christian concept of the word either. In fact, as you know from the New Testament, God does not require Christian OR JEWS today to be circumcised. (Colossians 2:9-17, Galatians 5:2-4, Romans 2:29). The covenant of circumcision with Abraham is no longer in effect. The word owlam means something like this. It means forever, or until the end of the age, whichever comes first. In fact, the age of the Jewish covenant has been ended when Jesus fulfilled the Law (Matthew 5:17). Yes, both the Old and the New Covenant are eternal/everlasting in the biblical sense of the word everlasting. The New Covenant will be in effect until the end of the age, which means that it will be in effect until Jesus comes back, bringing an end to the current age, and beginning on eternity. The drawing of the curtain on the church age and the coming of the eternal kingdom is described in Revelation 21-22. The Covenant between Israel and God, enacted at Sinai was everlasting, but it was everlasting until the end of the age, and that end came when Jesus ushered in a new phase in the kingdom of God. Jesus completed the Law of Moses, and “what is old and fading” has now disappeared (Hebrews 8:13). These examples show that everlasting does not mean for an infinite amount of time.
By the way, the Old Covenant, given at Sinai is also described as an everlasting/forever covenant in 1 Chronicles 16:15 and elsewhere. But, as above, the covenant is in force eternally, or until it is replaced by God with another covenant which brings the former age to an end. This happened in Christ.
The answer is yes, the New Covenant is everlasting, but we will not be under the New Covenant in heaven. Like God tells us in Revelation 21, “everything will be made new.” The “everlasting” New Covenant will be replaced by a different reality in heaven.
I know that this can be confusing. It is a matter of understand the meaning of a Hebrew word which is very difficult to translate into English in a way that our Western mind can understand that word.