Exodus 21:33

וכי יפתח איש בור AND IF A MAN SHALL OPEN A PIT which was covered over, and he now uncovered it. או כי יכרה OR IF A MAN SHALL DIG [A PIT] — Why is this stated? If he becomes liable for opening one that already exists how much the more is he liable for digging a new one! However, it does not mean that he digs a pit from beginning to end but it is intended to include in this law a person who digs after another has dug (i. e. who deepens to a height of ten handbreaths a pit which another has already excavated to a depth less than this. Before he did this an animal which fell into the pit was unlikely to kill itself; now, however, such a fall may prove fatal) — that such a one alone becomes liable (cf. Bava Kamma 51a). ולא יכסנו AND SHALL NOT COVER IT — if, however, he did cover it, though he did not fill it in with earth” he is not liable (Bava Kamma 50a). Scripture speaks of one who excavates a pit in a public thoroughfare (cf. Bava Kamma 49b). שור או חמור AN OX OR AN ASS — This is the law also with respect to all cattle and beasts, because wherever the Torah prescribes something with regard to “ox or ass”, we derive it (the fact that it applies to all cattle and beasts) on the grounds of the verbal similarity of שור in the text in question with שור which occurs in the law prescribing the Sabbath rest, for — with regard to the latter — it is stated, (Exodus 23:12) “that thine ox and thine ass may rest”. Now how is it in the latter case? We know that all cattle and beasts are to be treated in this respect as the “ox”, because in another passage referring to Sabbath (Deuteronomy 5:14) it is expressly said “[thy ox and thy ass] and all thy cattle”! So here, too, all cattle and beasts are to be treated as the ox. The only reason why ox and ass are alone mentioned is to imply: “an ox” — but not a man, “an ass” — but not vessels (Bava Kamma 53b).

וְכִֽי־יִפְתַּ֨ח אִ֜ישׁ בּ֗וֹר א֠וֹ כִּֽי־יִכְרֶ֥ה אִ֛ישׁ בֹּ֖ר וְלֹ֣א יְכַסֶּ֑נּוּ וְנָֽפַל־שָׁ֥מָּה שּׁ֖וֹר א֥וֹ חֲמֽוֹר׃

And if a man shall open a pit, or if a man shall dig a pit, and not cover it, and an ox or an ass fall into it;