Interpreting Paul's discussion of the weaker brother in Romans 14 has taken an interesting direction in recent years. Some of the younger Calvinists have tended to characterize the proverbial weaker brother as representative of a legalist perspective. In fact, in some circles the point is all but assumed as a settled matter. However, I'm not sure that this position squares with the original context or the text itself. Ever since first studying this portion of scripture, I've had a different take on the role of the weaker brother, namely that the believers represented are not legalists at all, but rather that Paul seems to be saying almost the exact opposite.
So, are some people who use the weaker brother argument legalists? Possibly.
... Although, Paul used it, and we know about as anti-legalistic an apostle as he could be.
In fact, legalists are typically in no danger of violating their consciences and are not tempted to participate in the action from which they are refraining and are urging others to refrain.
But is the weaker brother that Paul is talking about in Romans 14 a legalist? Absolutely not!
In scripture, legalists include folks like the Pharisees, the Galatian Judiazers, and the older brother in Luke 15.
They are almost always the prideful, "stronger" brothers or sisters.
Rather, Paul describes weaker brothers as tender souls who are entrusted to the care of the shepherds of the church in Rome.
In Romans14, Paul was exhorting those of stronger faith to not exercise their Christian liberty in a way that would cause those of weaker conscience to sin - don't flaunt your freedom.
This matter of exercising Christian liberty was NOT about proving wrong a bunch of legalists who were trying to impose their viewpoints on a bunch of young, idealistic pastors in the emerging New Testament church.
This was the well-seasoned, mature, founder of many early churches, Paul, looking out for new converts from a Gentile culture, riddled with extreme idol worship, passing into the holy communion of Christ-worshipping believers.
While I'm quite sure that converts from Judaism in Paul's day (much like the millennial/ emerging pastors of today who are rebelling against the legalism of fundamentalist churches), would have greatly desired to celebrate their liberty in Christ, Paul is pretty up front about how and why those of stronger faith should not give occasion for more tender believers to sin.
Paul also does not state, as some are inclined to believe, that we should 'teach Christian liberty' to weaker believers. While the knowledge and understanding of who we are in Christ can turn us away from false beliefs, it in no way validates teaching moderation when it comes to matters of conscience, which would amount to giving license to sin.
Those believers who have offered themselves as living sacrifices, to be transformed by the renewing of their minds, and to no longer be conformed to the pattern of this world, have little need for moderation when it comes to things of the world. And let's not forget, leaders will be held to a higher account.
Meanwhile, I grant, those of us concerned for our newer or more tender of faith members should be gracious toward stronger brothers or sisters whose consciences have not been as seared and wounded from being intensely immersed in worldly ways. And we cannot allow the weaker brothers and sisters to believe that their righteousness rests in abstaining from that certain thing about which they are convicted not to partake.
In either case, the principle take away from Romans 14 is that love takes precedence over personal liberty and matters of conscience. Guarding against legalism - earning salvation by works - is not really the point of the passage. We're called to sacrifice for one another and sometimes that means not exercising our liberty for the sake of others. Other times it means being genuinely glad for the freedom that others have to enjoy the things of the God's good creation.
Psalm 51:10 comes to mind, "Create in me a clean heart, O God; and renew a right spirit within me" -- Amen.