(Exodus 21:28) "And if an ox gore": The ox, too, was included in (Ibid. 12) "the striker of a man — if he die — shall be put to death." Scripture singled it out here for severity, (that it be put to death) by stoning. Thus, the adducing of this section.
The Torah States the Striker of a Man
Mekhilta Tractate Nezikin 10:1