Muwatta Malik 1568
موطأ مالك#1568SahihThese are the words of a Successor — the generation after the Companions — not of the Prophet ﷺ.
وَحَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ قَالَ كُلُّ نَافِذَةٍ فِي عُضْوٍ مِنَ الأَعْضَاءِ فَفِيهَا ثُلُثُ عَقْلِ ذَلِكَ الْعُضْوِ .
Yahya related to me from Malik from Yahya ibn Said, that Said ibn al-Musayyab said, "For every piercing wound in any of the organs or limbs of the body, one third of the blood-money of that limb is payable
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 43:17