You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled by men." (Matthew 5:13, NIV)Context: Matthew 5:1-16
Any government must show traits of integrity to be trusted. Even an unpopular style of government can be accepted if those in authority act with integrity. For example, a monarchy can work well even when nothing prevents the monarch from abusing authority if it has a kind, benevolent king, honest advisors, and virtuous subjects. Conversely, a democracy with ideal laws won't work if the people are corrupt. Even scientific discipline depends on the integrity of scientists who seek objectivity when making observations. Similarly, Christians need to be people of integrity to add a desirable seasoning to the world they live in.
As Christians, we want to attract people to Christ rather than repel them, but sometimes we need to be confrontational. During graduate work in engineering, students often salvaged used parts from old equipment to build our instrumentation. One day some technicians came into the lab complaining about not finding parts. The other graduate student I shared the lab with was out of town, and they found the parts they needed on his apparatus. Through intimidation and my unwillingness to confront them, I agreed to not tell they took the parts. Foolishly, I set myself up for a dilemma. When the student returned, he asked me who took the parts. When I didn't answer, he accused me. It wasn't hard for him to realize I knew what happened to them. When confronted, I confessed what happened. When the student told his advisor (their boss), the technicians were mad that I revealed their secret. They denied taking the parts and claimed I lied to cover up. The student only had to look at my equipment to see I didn't have the parts, but he found identical parts on the technicians' system. The student, my senior, told me not to let the technicians get away with taking parts from him again.
When Christians compromise their integrity to avoid confrontation, they lose the ability to flavor the world with Christ's example. They no longer help preserve their culture from spoilage, but become an object of ridicule and defame Christ's name.