Romans 15:14 says, "I myself am satisfied about you, my brothers, that you yourselves are full of goodness, filled with all knowledge and able to instruct on another."
Paul really does spell out a lot of important truths and key elements for understanding salvation and grace and our responsibilities as Christians in his letter to the Romans. And, although he says this statement above, he goes on to explain in verses 15-16 that he wrote with boldness the rest of Romans as a reminder, "so that the offering of the Gentiles may be acceptable, sanctified by the Holy Spirit." We are the Gentiles, originally not part of the chosen people, but who are now saved by the same grace as the Jews. Their rejection of Christ ushered in an understanding for the rest of us that he is our only hope of eternal life and salvation from what our sin has earned us, which is hell.
We, the elect, are saved by faith in Jesus Christ and sanctified by the Holy Spirit. Working in conjunction with our self conscience, the Holy Spirit makes us aware of right and wrong; and he prompts us and guides us in our decisions. If we listen and don't ignore Him, we will avoid the frustration of sin. We are only full of goodness if we are walking in the Spirit and striving to obey God's commands. We are sin apart from God.
Praise God for the Holy Spirit.