In Romans 12, Paul transitions from the theology of grace to its practice. (Note the “therefore” in the opening line of verse 1.) To borrow a quote from Spiderman, “With great power comes great responsibility.” Grace is a powerful force, and those who are the recipients of grace are given great responsibility.
First and foremost is the responsibility to submit and present ourselves to God as a living sacrifice. Paul describes this as our “reasonable service.” Some versions render this phrase as “spiritual worship” or some like phrase (ESV, NASB). The NIV is particularly bad, rendering the phrase “spiritual act of worship.”
Because of these renderings, some have adopted the false idea that all of what we do in life is worship. A casual study of the words generally rendered as “worship” or “service” will show the word here, latreuo, is normally rendered “service.” While all of life should be spent in service to God, by the definition of what constitutes worship, it is not possible for all of life to be worship. Worship is a specific type of divine service. (Think of it like this… all squares are rectangles, but not all rectangles are squares. Squares are a specific type of rectangle.)
Moreover, there is a great responsibility to the body. As seen in 1 Corinthians 12, the body is one but consists of many members. Being “members of one another,” and “having differing gifts according to the grace that is given to us, let us use them.” Each part of the human body performs a function necessary to the life, health, or growth of the body. So it is with the body of Christ.
Finally, we have a responsibility to our fellow man. Hearkening back to Jesus’ words in the Sermon on the Mount, Paul reminds his audience to “Bless those who persecute you; bless, and do not curse (v 14, cf Matt 5:44).
When we practice what is demanded by grace, we will not repay evil with evil, but rather with good. “If it is possible, as much as depends on you, live peaceably with all men” (v 18, cf Matt 5:9, Heb 12:14). We are never to be inclined to vengeance, but rather give place to wrath, for vengeance belongs to the Lord.
“Therefore, if your enemy is hungry, feed him; if he is thirsty, give him a drink; for in so doing you will heap coals of fire on his head. Do not be overcome by evil, but overcome evil with good.” In other words, put grace to work!