The Mekhilta explores a fascinating taxonomy of what can and cannot be redeemed in Jewish law. Certain consecrated objects can be redeemed — returned to ordinary status through a monetary payment. Others cannot. Certain forbidden foods can be redeemed. Items from which no benefit may be derived cannot.
Then comes a sweeping statement about the nations of the world: they cannot be redeemed. The proof is (Psalms 49:8): "A man cannot redeem his brother; he cannot give his kofer to God. Too costly is their soul's redemption and unattainable forever."
The Psalmist's words paint a picture of people for whom no amount of money can purchase spiritual liberation. Their souls are beyond the reach of monetary redemption — not because the price is too high, but because the transaction itself is unavailable to them.
By contrast, Israel occupies a unique position. Israel can be redeemed. The Mekhilta implicitly contrasts the nations' irredeemable status with Israel's access to mechanisms of atonement and restoration. The kofer payment, the Temple offerings, the rituals of repentance — these are instruments of redemption available exclusively to God's chosen people. The psalm is not merely poetry. It is a legal statement about who has access to the divine economy of salvation and who does not. Redemption is not a universal guarantee. It is a covenantal privilege.