Note 18 at Rom. 14:23: The Greek word that was translated "damned" here is "katakrino," meaning "to judge against; sentence." This differs from the Greek word "krino" that is used in 2 Thessalonians 2:12 to designate eternal damnation. "Katakrino," as used in this verse, actually means "to condemn" and is translated that way 17 other times in the New Testament. In contrast, "krino" is only translated as "condemn" once (Jn. 3:17), "condemned" once (Jn. 3:18), and "condemning" once (Acts 13:27).

Therefore, this verse is not saying that any Christian who does something with a defiled conscience is eternally damned. Paul is stating that any Christian who violates his conscience is going to come under condemnation.

Note 19 at Rom. 14:23: This verse provides us with a definition of sin that is applicable to all people of all cultures and different religious backgrounds. Any action is sin for us if we don't have faith in its correctness. Until we can settle our doubts, we aren't to do it. This would provide an infallible system for determining right and wrong for any individual.