Rebbi says: "Halving" is written in respect to the living ox, and "halving" is written in respect to the dead ox" — so it must be oxen of equal value of which Scripture speaks, (the halved shares of the dead ox, perforce being equal.)
Rabbi, the Title Given to Rabbi Yehudah Hanasi, the Compiler
Mekhilta Tractate Nezikin 12:4