Romans 12:1 says: “I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service.” Paul framed temperance in the context of a relational response, not a transactional context.
The text uses the word therefore, implying a concluding statement. In other words, Paul has just spent the whole beginning of the book of Romans bringing out the “mercies of God” in salvation by grace through faith in Jesus Christ alone. Salvation is free and cannot be earned. Then after Paul has spent the bulk of the book of Romans expounding on the “mercies of God,” he says, “Therefore present your bodies a living sacrifice.” In other words, our bodies are given to God as a response to the “mercies of God.”
Temperance is not a means of salvation. Temperance is a response of the heart that has been touched by the “mercies of God.” Our bodies are to be given to God as a “living sacrifice, holy, acceptable to God.” Temperance is the means through which we respond to God’s love. Paul then ends the verse with “which is your reasonable service.” In light of God’s mercies, giving our bodies to God is “reasonable.” Temperance does not earn our salvation; temperance is our reasonable response to salvation.