Midrash sobre Números 35:31

7) (Vayikra 24:21) ("And one who strikes a beast shall pay, and one who strikes a man shall be put to death.") I might think that if one blinded another's eye, his eye should be blinded; that if he cut off his hand, his hand should be cut off; that if he broke his leg, his leg should be broken; it is, therefore, written "one who strikes a beast," "one who strikes a man" — Just as one who strikes a beast pays, so, one who strikes a man pays. And if you would object: (But it is written [Bamidbar 35:31]) "You shall not take kofer (monetary payment) for the life of a murderer" — for a murderer you do not take kofer, but you do take kofer for (injury to) the limbs.

...An eye for an eye - one pays damage(s), the value of his eye. ...... Ben Azai says: behold here it says "a wound for a wound" and further on (verse 18) it says "if a man hits his neighbor with a stone or with the fist" - behold, this is the wound spoken. Just as the wound spoken of above "he will pay for his idleness and for his cure", here too "he will pay for his idleness and his cure". The wound is included in the general idea, and is expressed [lit. comes out] to teach (in general) and not about itself (specifically) - but it does come to teach regarding the general principle: just as the wound of which it is said "due to" is about payment, so too (here) [everything] of which it is said "due to" is about payment. Or - is it possible that this applies even for "life for life"? [No,] the text says (Numbers 35:31) "and you will not take ransom for the life of a murderer". [For the life of a murderer] you do not take payment, but you do take payment for limbs.

"and its owner, too, shall die": at the hands of Heaven. You say at the hands of Heaven, but perhaps at the hands of man? It is written (Numbers 35:31) "You shall not take kofer (ransom) for the soul of a murderer, who is liable to death" — Redemption is not given for those who are put to death at the hands of man, but (only) to those who are liable to death at the hands of Heaven.