What is "covenant-cutting" (karat brit), and how is the cross one?

If "covenant" lands on your ear as "contract," that is simply how the word reaches us in English, and it is not your fault. And you are right that something solemn and weighty is happening at the cross; that instinct is sound. And if penal substitution never quite satisfied you, hold that; it is pointing somewhere true.

The error is reading the cross through the ledger, debt and payment and transaction, because that is not how a covenant gets sealed. To "cut a covenant," karat brit, was as concrete as it was severe: the animals were cut in half, the pieces laid in two rows, and the parties walked the bloody aisle between them, saying with their bodies, "let it be done to me as it was done to these animals if I break my word." In Genesis 15, Abraham (Abram) falls into a deep sleep and God alone passes between the pieces, taking both sides of the covenant onto Himself. The cross is that same act in flesh: the covenant-cutter shedding His own blood to seal the promise, the smoking torch of Genesis 15 now walking the aisle in a body. Not a payment rendered. A covenant cut.

Do not take it from me. Read Genesis 15, the whole chapter, then Luke 22:20 where Yeshua (Jesus) calls the cup "the new covenant in My blood," and ask whether the cross is a ledger balanced or a covenant cut.