When a Jewish man and woman get married they are bonded with Hashem . You shall not steal. The very foundation of community depends on whether or not you can trust your neighbor not to ride off with your bike or pick tomatoes from your garden without your permission. Someone who steals is saying they don't want to be a trusted part of the community. You shall not bear false witness against your neighbor.
Truth is another building block.
Especially in court. You've got to be able to count on witnesses to tell the truth. Even among friends, those little lies that we think of as good fun are really wrong. The Torah warns us not to let false witnesses get away with lying, otherwise Hashem will turn away from Eretz Yisroel. No rain will fall and drought will result in a terrible famine.