A covenant is a principle of relationship with God on the earth-conditions established by God under which man is to live with Him. The word may, perhaps, be used figuratively or by accommodation. It is applied to details of the relationship of God with Israel; but strictly speaking, there are but two covenants, the old and the new. The old was established at Sinai. The new covenant is made also with the two houses of Israel.
The gospel is not a covenant, but the revelation of the salvation of God. It proclaims the great salvation. We enjoy all the essential privileges of the new covenant, its foundation being of God; but we do so in spirit, not according to the letter. The new covenant will be established formally with Israel in the Millennium.