פּירוש אויף שמות 21:36

או נודע means, OR it was not a תם but IT IS KNOWN THAT THE OX WAS WONT TO THRUST to-day yesterday and the day before yesterday — thus you have the three acts of goring required to make it a שלם ישלם שור (Bava Kamma 23b)

., “and he had not secured it;” actually we could have learned this by simple logic. If an owner of an ox that had gored must bear half the cost of the loss of its victim if the offending animal had had a reputation for aggressiveness and its master had not secured it, he surely must be liable for the whole damage! Why do we need the words: “and he had not secured it?” Therefore we learn that this word speaks another type of guarding that ox; he has to also muzzle such an ox so that it cannot become guilty of causing damage with its mouth, by either biting, or grazing in other people’s fields. An alternate explanation why the words: ולא ישמרנו are needed; logic does not suffice to impose penalties. Perhaps someone could come up with another aspect nullifying our logic. Therefore penalties have to be spelled out. Still another interpretation: the penalty applies even if the offending ox had been looked after on behalf of its owner by someone who did not charge the owner a fee for this.

OR IF IT BE KNOWN THAT THE OX WAS WONT TO GORE IN TIME PAST, AND ITS OWNER HATH NOT KEPT IT IN, HE SHALL SURELY PAY AN OX FOR AN OX. It is known that if a Tam¹⁹³A Tam is an animal which has not injured, or killed [an animal] more than three times and whose owner has not been warned that it is dangerous and must be guarded. For whatever damages a Tam does, its owner pays only half the loss. The Tam is distinguished from a Muad, an animal which has killed or injured at least four times, and whose owner has been warned that it is dangerous and must be guarded. For whatever damage it does, the owner must pay in full. too is properly guarded by its owner, but through an accident it so happened that it went out and caused damage, the owner is certainly not liable.¹⁹⁴But if so, the question arises why the Torah mentions the guarding of the animal only in the case of the Muad, (see Note above) since the same law applies to a Tam as well. Ramban proceeds to remove this difficulty. Thus the reason why He states only with reference to a Muad,¹⁹³A Tam is an animal which has not injured, or killed [an animal] more than three times and whose owner has not been warned that it is dangerous and must be guarded. For whatever damages a Tam does, its owner pays only half the loss. The Tam is distinguished from a Muad, an animal which has killed or injured at least four times, and whose owner has been warned that it is dangerous and must be guarded. For whatever damage it does, the owner must pay in full. and its owner hath not kept it in, [when the same principle would apply to a Tam as well] is, according to that Sage in the Talmud¹⁹⁵Baba Kamma 45b. See in my Hebrew commentary p. 426, that the reference is to Rabbi Meir. who says that a Muad needs better guarding than a Tam, as follows: Scripture states that if the ox was wont to gore and warning had been given to its owner, and he hath not kept it in and guarded it better in view of its dangerous nature, so that it went out and caused damage, the owner must pay the full damage. According to the opinion of that Sage¹⁹⁶This is the opinion of Rabbi Eliezer ben Yaakov (ibid.). who holds that the degree of guarding necessary for both Tam and Muad¹⁹³A Tam is an animal which has not injured, or killed [an animal] more than three times and whose owner has not been warned that it is dangerous and must be guarded. For whatever damages a Tam does, its owner pays only half the loss. The Tam is distinguished from a Muad, an animal which has killed or injured at least four times, and whose owner has been warned that it is dangerous and must be guarded. For whatever damage it does, the owner must pay in full. is alike, the meaning of the verse is as follows: If it be known to the owner that the ox was wont to gore and now too [i.e., at the fourth time] he hath not kept it in, he is liable to pay the full damage on account of his grave negligence.

.מועד HE SHALL SURELY PAY AN OX [FOR THE OX] — i. e. the full damage.