The book of Romans is an extended letter written by Paul, an apostle. Paul shares with his fellow Jews that adherance to the law is not sufficient for salvation. Faith in Jesus Christ and repentance of sin are necessary for salvation.
In Romans 3:28 Paul states "For we maintain that a man is justified by faith apart from observing the law." Paul teaches that outward works will not gain a place in heaven, only an inward change of the human heart will suffice. And, only Jesus/God/Holy Spirit can help change our hearts.
Paul also teaches that human beings are naturally inclined to sin. The remedy for this is faith that Jesus Christ died for our sins and that we can begin again through Him.
Romans 4:24-25 "He was delivered over to death for our sins and was raised to life for our justification".
Paul also stresses that though Christians are independently gifted by God to assist one another (teaching, encouraging, giving, leading, showing mercy, etc.) we are to use our gifts to glorify God and serve one another as the body of Christ.
He reminds us too, to remain humble servants. Romans 12:3 "For by the grace given me I say to every one of you: Do not think of yourself more highly than you ought, but rather think of yourself with sober judgement, in accordance with the measure of faith God has given you."