In Romans, when Paul writes concerning what sin is for a Christian, he uses a word that has the meaning of “to thoroughly judge”, which is translated as “doubting” or “making a distinction”

But the one doubting, if perhaps, he should eat is condemned because it is not out from faith. And all which is not out from faith is sin. – Romans 14:23.

Since sin involves doing something that is not out from faith, doubting is questioning what is permissible. Therefore, when we do something that is contrary to what we have determined within our minds is permitted by God for us as Christians, we are not taking God at His Word. This involves a battle with the conscience, for it will either excuse or accuse us based upon our knowledge and actions (Romans 2:15). One who is doubting is thoroughly judging ways to get around their conscience to justify doing something that they know is wrong. Typically, this type of a situation comes about by the influence of others. We are instructed in Romans 14:1 to accept the weaker in the faith brother, but not for the purpose of thoroughly judging their beliefs. And neither is to seek to influence the other with the way they have chosen to separate themselves out to God (Romans 14:10). One may choose to abstain where the other does not. This is not permitting sin in the assembly, but how we each govern our own bodies before God.

James also uses this same word to describe someone who is not asking out from faith. Describing this type of a person as one who is like a wave of the sea that is driven by the wind and tossed (James 1:6). These are […]