I assembled this flow chart to help group members understand that the Old Covenant, alluded to in the book of Hebrews, is the Holy Covenant. It is also an appendage of the "everlasting covenant". If you look at the flow chart, you will see that the Holy Covenant will continue to be employed until the 7 last plagues (the unbridled wrath of God) has completed. To validate that the Holy Covenant will be a major factor in the last days, please read Daniel 11:28-30.
The Holy Covenant was set in place so that the testimony of good and evil could continue until rebellion will be allowed a full manifestation. This manifestation will occur at a time of the Father's appointment. The Holy Covenant is like a braking system that slows down the compounding effects of the great rebellion. Without this breaking system called "Israel", society would spin out of control as it did prior to Noah's flood. Yeshua said of Israel "you are the salt of the earth" (meaning the preservers of mankind).