To respond to Bryan's questions:
1. whether to stone the adulterers: it's never the common people's decision nor had they the authority to do so. It was in the hands of justice system i.e. the priests who were given the authority at that point in time. One might argue that believers are priests but one should know the governments we are under do not give believers the authority to judge i.e. no mob law allowed.
2. sacrifice: I'm surprised he raised this question at all when he seemed to understand the letter to the Hebrews - or - he might just be ignorant to the Scriptures in several ways:
a. The Law specified where, i.e. the temple, to offer sacrifice. God allowed the temple to be destroyed around 70 AD to stop any sacrifice, whether out of ignorance or disbelief in the Messiah's atonement. So no temple, no sacrifice is a known fact among both Jews and Christians.
b. The Scriptures teaches: To obey is better than sacrifice, and to heed is better than the fat of rams. cf 1 Samuel 15:22
c. God desires mercy, not sacrifice, and acknowledgment of God rather than burnt offerings. cf Hosea 6:6
d. The gospel clearly says the Messiah is the Lamb who takes away the sin of the world. cf John 1:29 and 1:36
e. Hebrews 7-10, which Bryan quoted for some reason other than addressing the issue, clearly stated why animal sacrifice is no longer valid, whether or not there is a temple.
3. cancellation of debts: his question is best addressed to the banks where many Christians work as loan officers. As to individual Christians, yes why don't they obey this law?