Chapter 20:
Why do you think God prefers the people residing in the land to be slain rather than forced to move somewhere else?

Ted: If they had been forced to move elsewhere, they would have returned again and again to attack the Israelites. If they had been absorbed into the Israelite society, they would have influenced the Israelites to worship their own gods, thereby causing the Israelites to sin.

Chapter 22:
I think some of the rules in 22 are strange, like not yoking an ox and a donkey together, but we talked about God giving them trivial rules.
Ted: I agree that some of the rules appeared trivial, on the surface. Yet it seems that God always had a "higher" reason for each of His rules. Perhaps yoking together two unequal animals had something to do with Paul's instruction for a believer not to be "yoked" with an unbeliever (2 Corinthians 6:14-17).

For instance, such a detrimental yoke might be in the marriage between an believer and a non-believer, where the non-believer might cause the believer to stray away from God, and also might not pull his/her own spiritual "weight" in the marriage, forcing the believer to work too hard to make the marriage work. Likewise, pertaining to the ox and the donkey, the stubborn donkey might not do his share of the work, forcing the strong, industrious ox to work too hard at getting the job done.