Under the Old Covenant, God promised to keep covenant with those who kept His commandments. If the commandments are not kept, God no longer has to keep covenant with you.
Again, we rejoice we are not under the Old Covenant because of this. But again, let us note carefully why this is so. Here is how the reality of the New Covenant is described in Ezekiel 36:27:
“And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them.”
With the Spirit we fulfill the righteousness of the Law. The Law is not burdensome, it does not inspire sin and death. On the contrary, it is the evidence of true spiritual life.
Keeping the Law consists of loving the Lord your God and loving your neighbor as yourself. Love is the fulfilling of the Law. Christ is our example. The Gospel, the greatest demonstration of love, is our life.
Those who have the Spirit are those who are in true covenant with God. We meet our end because the Spirit is in us, working through us, stirring up gifts, producing fruit, etc.
The New Covenant is a better covenant because it meets all the conditions that God desires to be met. How great our God. How great His gracious provision received by faith.