In order to demonstrate his teaching, Paul brings up an example from the early church, showing how to handle a deep difference of opinion. One believer sincerely believes it is OK to eat anything; another, with a weaker conscience, will eat only vegetables.
A bit of background here. This letter was written to Christians in the city of Rome; as such, the meat under discussion was not raised on the Christians’ personal farms. In that place and time of multiple pagan gods, the meat in the marketplace was often part of a sacrifice to the gods. Particularly to Christians of a Jewish background, eating this meat could appear very much like participating in worship of idols.
Paul’s answer to this dilemma was twofold: the brother who could eat anything is not to despise the brother who cannot, while the brother who can’t eat the meat is not to judge the brother who does. God has accepted both brothers.
To put this direction into practice is often harder than it seems. Christians, with their awareness of eternity, live for the highest possible stakes. Decisions have eternal consequences, and no one can afford to be ultimately wrong. Thus, beliefs take on extra weight and sincerity; disagreements run much deeper, as neither side is willing to give up their conviction of what is right.
And so, Paul tells us to look away from each other, to look away from the circumstances. God, he says, has accepted the brother who eats that meat you are sure is contaminated by idols; leave him to God. And, if you are the brother living in liberty, if you know that the giving of thanks to God cleanses the food you eat, regardless of its origin, make sure you are not looking down at your sensitive brother. A quick look back at what God has done for you, what He has saved you from, should be enough to turn your thoughts to gratitude toward God and love for your fellow believer.