Romans 12:3-5 meaning

In order to pursue righteousness—that which is right and results in harmonious living—we must live sacrificially through faith (as Paul said in verse 1). Paul is promoting transformative principles, not a to-do list. He is endorsing attitudes, not rules to follow. Living sacrificially means having humility and living to benefit others. Humility is the willingness to see reality as it is.

Much of humility comes from the recognition that God is God and we are not. God has given us everything we have. To live sacrificially, we must realize that everything we are and have to offer comes from God. Paul exemplifies this humility with his preface to the following verses: Through the grace given to me I say to everyone among you (v 4). He acknowledges all the wisdom and knowledge he imparts to his audience comes from God, not him.

The Greek word "charis" translated grace means "favor." Context determines who is granting favor and for what reason. An example is in Luke 2:52 where Jesus grew in "favor" ("charis") with God as well as with people. We can presume God was mainly looking at Jesus's heart, and the people were looking at His behavior, but each decided what Jesus was doing was favorable. 

In Paul's case, God granted him the favor of showing him his sin and calling him out of futility (Acts 9:3-6). God further called him to be an apostle to the Gentiles, and to suffer for His name (Acts 9:15-16). In each case, God favored Paul because He chose to do so, greatly to Paul's benefit. Paul recognizes this reality. 

We are admonished to see things as they are, as Paul did. It is our natural bent to think of ourselves more highly than we ought to, but God tells us to see ourselves as we actually are, no more and no less. It is important not to think more highly of himself than he ought to think; but to think so as to have sound judgement (v 3). This is extremely important if we are to live a life of righteousness, because righteousness is all parts of the body working for the good of the whole. 

So if we say, "I am only a little toe, and little toes are not important, therefore I will just not do anything," then the body is without a little toe. Anyone who has ever had an injured little toe discovers just how important a little toe really is. It is deeply necessary that we learn to identify our gifts, whatever they are, and use them to serve others—regardless of whether the world honors that gift (1 Corinthians 12:20-23).

We will soon learn how each person has a gift they can use to serve others. But it takes faith to believe that such service to others is really important. And God has allotted to each a measure of faith (v 3) for us to exercise. It is a part of our logical service as a living sacrifice (Romans 12:1) to exercise the faith we are given by employing the gifts we received to serve others.

Paul continues this thought on humility, which is seeing things as they actually are, and its importance to a life of harmonious and righteous living through faith. He does this by discussing how we, as believers, come together to form a body. 

Paul uses the analogy of a body to explain how each of us, though individually and uniquely gifted, should come together to form one cohesive unit: We have many members in one body and all the members do not have the same function (v 4). 

The Christian life is not intended to be lived alone. To live righteously, harmoniously with others, we must be in community and fellowship with others. Life is, therefore, a team sport. We each need to play our part on the team in order to benefit the team. 

And to live harmoniously we must have the humility to understand what part of the body we are, as well as be aware enough to appreciate and rely upon other parts of the body. We, who are many, are one body in Christ and individually members one of another (v 4). 

There is one body with many parts. Each part of the body has value. Each part of the body should be honored appropriately (1 Corinthians 12:20-23). Living in community with other believers is something we do every day, all day long, not just at a scheduled time each week. And living harmoniously is something we do unilaterally, regardless of whether others respond. To play our assigned role with good stewardship is living life as a living sacrifice, which pleases God (Romans 12:1). 

To please God is the ultimate goal in life for humans. It is in pleasing our Designer that we are most fulfilled (1 Thessalonians 4:1-3).