The Old Covenant was a bilateral covenant of which Yahveh and the nation of Israel were parties. The Israelites had to agree to the terms of the covenant, which they did (Exo. 24:7).
Is the New Covenant a bilateral covenant?
Yes, it is a bilateral covenant! This is the new covenant, Jeremiah 31:31-34 (NIV) :
This new covenant started when Jesus poured out his blood (symbolized by the wine in the last supper), Luke 22:20 (NIV):
All we have to do to accept this new covenant is stated in Romans 10:9-12 (NIV):
Jesus basically stated the "terms" in John 15:5-7 (NIV), though not speaking specifically about a covenant:
Yes, the New Covenant is a bilateral covenant, and Dan the Man covers many of the salient points. I would also like to add a few points from the book of Hebrews, which gives a beautiful and in-depth description of how the New Covenant is so much better than the Old Covenant (Starting in Heb 7:11 and running through the end of chapter 10).
But first, here's how I'm using the terminology. A covenant is an agreement between two or more parties (basically a contract--verbal, written, or otherwise). A bilateral covenant is the kind we're most accustomed to, where both parties are expected to consent to the agreement before the agreement comes to life and is seen as valid and enforceable. That is, unless and until both parties agree to abide by the covenant/contract, there is no covenant/contract. A unilateral covenant is an agreement where one party agrees to do something regardless of the approval, interest, commitment, compliance, or participation of the other parties. There is still a commitment and contract being made. One party is still obligated to follow through on everything in the covenant. However, the responsibility to follow through is not dependent on the participation or behavior of the other party(ies). This would be like a man on his wedding day saying to his bride, "I promise to love you, for better or for worse, all the days of our lives." His promise is unilateral, and does not depend in any way on the performance or acceptance of his bride.
So in Heb 7:23-25, the writer says,
Here we see that salvation is not strictly unilateral. It doesn't take effect unless/until we draw near to God through Jesus. Again, it's not the difficulty or effort involved that makes a covenant or contract bilateral. If there is any requirement on the other party to do anything at all for that covenant or contract to go into effect or to stay in effect, then it is not unilateral.
"But wait," you might say, "the author here is talking about salvation...he hasn't said anything about the New Covenant per se." The writer is indeed speaking of the New Covenant here, and it will become clear over the next couple of chapters. Up till this point in Hebrews, the writer has been laying the groundwork of how much more excellent Jesus is than the earthly priesthood that had preceded him, and now he's going to show this even further, in the context of how much better the New Covenant is than the Old Covenant.
In Hebrews 8:7-13, the writer makes the definite tie-in between the New Covenant and the Old Covenant, saying:
Here the writer of Hebrews is making direct reference to the Jeremiah 31:31-34 where the Lord foretells the future coming of the New Covenant. And after continuing his comparison of the New and Old Covenants in chapter 9, the writer says in Heb 10: 19-31,
Now at this point, some might say, "Hey wait a minute, wasn't the book of Hebrews written to Jews? Does this all really apply to me?" Well yes, it was written to Jews. It was written to Jews who had chosen to believe in Jesus, but who were struggling with their connection to the Old Covenant and what it now meant to be a Jew and a follower of Jesus. The ultimate question for these Jews was where the Old Covenant, Moses, all the Jewish traditions, and their now-tenuous connection to the Jewish community all fit in with life in Christ. So the writer of Hebrews was saying to them, "Look brothers, you formerly trusted in the old sacrificial system to cover your sins, but that's no longer available. So now, having heard that the only way for your sins to be cleansed is through Jesus, you really must come to him! Because if you don't, you have nothing to rely on under the Old Covenant anymore. Fellow Jew, don't be tempted to leave your trust in Jesus and return to the Old Covenant! It's kaput. It's done. Unless you come to Jesus and stay, your only future expectation is a fiery judgment."
So it was necessary for the Jew to "do something" in order to enter into the New Covenant. First, he had to willingly leave his place of reliance on the Old Covenant. And then, he had to place that trust and reliance solely upon Jesus. And it's no different for the Gentile. We all are inaugurated into the New Covenant in the same fashion. We must leave our trust and reliance upon anything else for our righteousness, and place that hope firmly and solely in Jesus.
So the New Covenant is bilateral. Our part is to come to Jesus, and to trust in him completely. The New Covenant is truly beautiful, truly powerful, and truly better than the Old Covenant it replaced. The New Covenant works (where the Old failed) because there is so much less for us to do, and so much more for God to do. In fact, if it weren't for the "coming" and "trusting" part, the New Covenant would be completely unilateral. We simply come to Jesus and trust him fully, and in doing so, he changes us completely and comes to dwell within us. This is what makes the New Covenant work--Christ in us, because where the Old Covenant was lived out by man's power and resources to obey, the New Covenant is lived out by Jesus' power and resources to obey. The New Covenant is so much better because Jesus is perfect, and because under this New Covenant it is no longer I who lives, but Christ lives in me, and this I do by faith in the Son of God, who loved me and gave himself for me!
The First Covenant is unilateral:
My understanding on this point comes from a sermon by Tullian Tchvidjian, but I have found similar explanation of contract covenants at the time:
But in our story, we only see one party-- the smoking firepot representing God-- doing the walking. Paul confirms this (see also Romans 11):
The Second Covenant is unilateral:
From a sole fide or sola gratia perspective, the New Covenant is inherently unilateral.
Probably the most famous verse on grace - Ephesians 2:8-9, states it explicitly:
A bi-lateral covenant would entail work on the other party. Grace (meaning "Gift") explictly rejects that. To say otherwise to someone who values grace tells me that a child receiving a christmas present has likewise entered into a bilateral covenant. Try telling my kid that.
God's covenant's are neither unilateral nor bilateral, but they are colateral, meaning that even though Jesus" has been made a propitiation for us and taken the anger of God on our behalf and is the mediator of the new covenant, The covenant itself, set up by God himself to reconcile his creation, man, male and female, back to himself, this covenant is made solely by and offered to us by God, it is his covenant, made in Jesus' blood, but we must accept that covenant or not accept it, therefore we must enter into it and agree upon the conditions of the covenant God offers to us by faith in His Son, so this is a colateral covenant that requires both sides to believe in and abide by the covenant. Jesus, the mediator of the covenant offers to each person as a free gift but they must receive it by faith. Jesus said , if, which is conditional, you abide in me and my word abides in you, and those that have the spirit of Christ abiding in them they are his. We must do our part and abide in Him as he has stated in his word and continue in Him by faith. It is a colateral covenant which is dependent on both parties doing their part in the honoring of the covenant.
Just like the covenant to Abraham, Noah, Moses; perpetual priethood,; David; "you shall never lack a man to sit on the throne"; The New and Everlasting Covenant, by the blood of Christ, offered in the heavenly holy of holies, is a one party Covenant. The NC is a one party covenant %100 due to Christ's blood as HE DID IT ALL!!! This testimony is the spirit of prophecy!! Christ's preeminence is key here. Any other speculation is anti blood of Christ in the context of scripture. The OLD and NEW Covenant's must not be homogenized as this is merely refried legalism and in affect de-values Christ's blood in others minds.