DEUT1172 Do not work two different species of animal under the same yoke. Key concept: According to the Rambam this mitzvah is connected to the Torah’s prohibition on crossbreeding (See [[LEV742]] Leviticus 19:19 mixed CHINUCH 154-5). Were it permitted to tie different species of animals to the same yoke, the animals probably would be housed in the same barn and the owners would be tempted to engage in crossbreeding. For this reason, working different species together is prohibited. The Sefer HaChinuch offers a different reason: The Torah forbids us to cause pain to any creature. Animals and birds experience great discomfort when they dwell with creatures that are not of their kind. All the more they experience discomfort when they are forced to work side by side with a different species. We observe that when animals are allowed to roam free, they cling exclusively to their own kind. The wise at heart should be take note of the above and be aware that when two people must be appointed for any given project or task, one should not appoint people who are vastly different in terms of their nature or behavior. For example, do not make a righteous individual work with someone who is known for wickedness. Do not pair up someone of noble character with someone who acts as if he has no shame. We see that the Torah forbids unfit pairing of animals--creatures that are practically devoid of all intelligence. All the more so must we be careful not to create inappropriate pairings of human beings, who think and understand.