What does Romans 14:16 mean?

Paul has warned, in the previous verse, that if those with a strong faith insist on carelessly exercising freedom in Christ, they may do damage to someone of weaker faith. How could this be? Paul has written, for example, that if someone lacks conviction that they are free in Christ to eat meat, then eating meat is unclean for them. If they eat meat, in violation of their conscience, that for them would be a sin. This, even though eating of meat in general is not sinful.

This is the application of Paul's earlier remark about creating a stumbling block (Romans 14:13). An inconsiderate demand to exercise freedom in Christ could lead someone with weaker faith to violate their own conscience. That demand might cause another to "stumble" into sin. Now Paul says if that were to happen, it would cause a good thing—freedom from the restrictions of the law for those in Christ—to be spoken of as evil. This means careless and proud exercise of freedom in Christ can damage those it leads violate their own conscience and mar the reputation of such freedom itself.

In other passages, Paul's teaching clarifies that this does not give those "weak in faith" the right to police the choices of other Christians (1 Corinthians 10:29–30). Merely knowing that another believer holds a different opinion is not, in and of itself, a "stumbling block," and that is not cause for the "weak in faith" to judge or accuse them of sin (Colossians 2:16–23). Rather, Paul's point is that flaunting freedom in front of those who feel conviction is wrong; it's an abuse of our Christian liberty.