(Exodus 21:35) says: "And if the ox of a man strike" — the Mekhilta immediately draws a legal boundary. The phrase "of a man" excludes the ox of a minor. A child who owns an ox that causes damage is not liable under this verse. Legal responsibility for animal torts requires the owner to be an adult with full legal standing.
But the Torah also says "the ox of his neighbor." The word "neighbor" has multiple implications. First, it includes the ox of a minor as a potential victim — if someone's ox gores the ox of a minor child, the adult owner is liable. Second, the word "neighbor" excludes certain categories of non-neighbors from the law's protection.
Specifically, the Mekhilta lists those excluded: the ox of a Cuthite (Samaritan), the ox of a gentile, and the ox of a sojourning proselyte (a ger toshav — a non-Jew who has accepted certain basic laws but has not fully converted). None of these are considered "your neighbor" for purposes of this verse.
This passage reveals how the rabbis used every word in a verse to define the law's scope. "A man" establishes who can be liable. "His neighbor" establishes who is protected. Between these two phrases, the Torah draws a complete map of who is inside the system of animal tort law and who is outside it. Every word adds a wall or opens a door.