"You shall not see the ox of your brother": a negative commandment. And elsewhere it is written "If you encounter" — a positive commandment — whence we derive that (in the event of non-compliance) he transgresses a positive and a negative commandment.
"the ox of your brother": This tells me only of "the ox of your brother." Whence do I derive (as included in the mitzvah) the ox of your foe? From (Ibid.) "the ox of your foe" (i.e., in any event). If so, why is it written (here) "your brother"? Scripture (there) speaks only anent the evil inclination (i.e., Restore not only the ox of your brother, but even the ox of your foe — above the protestations of your evil inclination.)