by Richard Sibbes
The third period of renewing the covenant of grace was from Moses to Christ; and then it was more clear, whenas to the covenant made with Abraham, who was sealed with the sacrament of circumcision, the sacrament of the paschal lamb was added, and all the sacrifices Levitical; and then it was called a testament. That differeth a little from a covenant; for a testament is established by blood, it is established by death. So was that; but it was only with the blood and death of cattle sacrificed as a type.
But now, to [from] Christ’s time to the end of the world, the covenant of grace is most clear of all; and it is now usually called the New Testament, being established by the death of Christ himself; and it differs from a covenant in these respects:
First, A testament indeed is a covenant, and something more. It is a covenant sealed by death. The testator must die before it can be of force. So all the good that is conveyed to us by the testament it is by the death of the testator, Christ. God’s covenant with us now, is such a covenant as is a testament, sealed with the death of the testator, Christ; for “without blood there is no redemption,” Heb. 9:22; without the death of Christ there could be no satisfaction, and without satisfaction there could be no peace with God.
Secondly, A testament bequeatheth good things merely of love. It giveth gifts freely. A covenant requireth something to be done. In a testament, there is nothing but receiving the legacies given. In covenants, ofttimes it is for the mutual good one of another, but a testament is merely for their good for whom the testament is made, to whom the legacies are bequeathed; for when they are dead, what can they receive from them? God’s covenant now is such a testament, sealed with the death of Christ, made out of love merely for our good; for what can God receive of us? All is legacies from him; and though he requireth conditions, requireth faith and obedience, yet he himself fulfilleth what he asketh, giveth what he requireth, giveth it as a legacy, as we shall see afterward.
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From Richard Sibbes, The Faithful Covenanter, in Works, vol. 6, p. 4.