garee,
re: "I would ask what does the metaphor 'heart of the earth' represent?"
For the purpose of this specific topic it represents the tomb. Is that what the Messiah meant it to mean? Maybe, maybe not. It doesn't matter because this topic is directed to anyone who thinks it is referring to the tomb. If you want to disagree with that thinking, then you should start a new topic.
Heart of the earth is reckoned as a three day work of suffering the pangs of hell as the tribulation or wrath of God using three to represent the end of the matter." Belly of the whale" is another idiom meaning the same .
Tomb or buried I am sure that is not what he meant. Three days and nights in the heart of the earth is not three days in the grave or the tomb. It is compared to Jonas 3 days and three nights
alive in the belly of the whale. Suffering the pang of hell , as a living work of Christ. it is reckoned as is the "living sacrifice". No dead sacrifices .Dead works as work that do not provide spirit life have no spirit life needed.
He began the work of suffering in the garden on Thursday as the father and son worked together to bring the peace of God that surpasses all human understanding.
Saying, Father, if thou be willing, remove this cup from me: nevertheless not my will, but thine, be done.And there appeared an angel unto him from heaven, strengthening him. And being in an agony he prayed more earnestly: and his sweat was
as it were great drops of blood falling down to the ground.
Luke 22:42- 44