Note 5 at Ro 14:3: Paul was preaching about having a tolerance for other believers who had differing views that may have appeared contradictory to his own actions. However, as explained in note 3 at Ro 14:1, these were not believers who were putting faith in these actions for salvation; they wouldn't have been true Christians if they had. These people were justified by faith, but they had a personal conviction about keeping the ceremonial law of their Jewish heritage.

These people were different from the ones that Paul spoke of in his letter to Timothy. In 1Ti 4:1-3, Paul said those who commanded others to abstain from meats were speaking a doctrine of devils. The key difference is the word "commanding" (1Ti 4:3). Those in 1Ti 4 were demanding compliance for salvation. The people that Paul was saying to receive in this verse were people who were not judging others for their own personal convictions.

Note 6 at Ro 14:3: Notice that Paul instructed those who have the revelation of their freedom in Christ not to despise those who don't. He also instructed those who are still emphasizing works not to judge those who aren't.

Paul was revealing that the danger for those who have a revelation of God's grace is to become insensitive to and impatient with their brethren who haven't yet come to that knowledge. Those believers have to temper their freedom in Christ with love for their fellow Christians. "Knowledge puffeth up, but charity edifieth" (1Co 8:1).

Those who have not yet renewed their minds to their freedom from the Old Testament Law tend to be judgmental of others who don't have their same standard of holiness. Passing judgment on others is a sure sign of a legalistic mentality (see note 46 at Mt 7:1).