Why were “the graves…opened,” and why does it say that “many bodies of the saints which slept arose, and came out of the graves after (Christ’s) resurrection”?
My understanding is that this was done as a manifest token of the Lord’s successfulness in having functioned as Israel’s Redeemer, and in doing so fulfilling the first mandate of the Davidic Covenant. In particular that first mandate had as one of its components the issue of the Redeemer providing for the fulfillment of what was declared, for example, in Hosea 13:14. There God said, “I will ransom them from the power of the grave; I will redeem them from death: O death, I will be thy plagues; O grave, I will be thy destruction: repentance shall be hid from mine eyes.”
In accordance with the significance and meaning of His name “Jehovah,” God Himself would become Israel’s Redeemer. And the Davidic Covenant, with its provision for David’s Lord to become David’s son, is the mechanical means for the implementation of God’s “Jehovah-ness.” Specifically the first mandate of the Davidic Covenant called for the Lord to function as Israel’s kinsman-Redeemer, and thereby to provide for all the aspects of redemption that Israel needed, including redeeming them from death.
Now in view of the fact that the Lord through His own death and victorious resurrection succeeded with the aspect of redemption that would “redeem them from death”; and in view of the fact that the saints of Israel wouldn’t actually be receiving the full benefits of it until the first resurrection; my understanding is that the event of Matthew 27:52-53 served as both a manifest token to them of the Lord’s successful redemptive work spoken about in Hosea 13, as well as an earnest of the resurrection to come for all the saints of Israel at the first resurrection.
The doctrine of redemption (as set forth in the Law) does provide for such a thing as a token to be given in connection with redemption. The token signifies to all concerned the fact that the redemption has been accomplished, and that it is legal and indisputable. [Note: Interestingly enough a token can even be given preceding redemption to signify who the redeemer is, which is something the Lord also gave when He entered into Jerusalem before going to the cross.]
According to the account in Matthew 27, when these saints “came out of the graves after (the Lord’s) resurrection, and went into the holy city, and appeared unto many,” it was the last of three particular manifest tokens concerning the successfulness of the Lord’s redemptive work. The first is the rending of the veil of the temple; the second is the quaking of the earth, with the rending of the rocks, and the actual opening of the graves; and the third is the arising of these saints out of the graves and going into the holy city after the Lord’s resurrection. Through these three specific manifest tokens the particular issues of the Lord’s redemption that pertained to sin and death were signified to have been successfully accomplished.
– K.R. Blades