Romans is the first of the Epistles.
After the five Historical Books of the New Testament, the Bible continues with the Epistles. These are letters written to teach and instruct Christian doctrine. The first nine of the Epistles were written by Saint Paul, and the first is called Romans. It was written whilst Paul was in the Greek city of Corinth, around 56 AD, to the Christians in Rome, a place Paul had not yet visited. He writes to introduce himself and asks the people there to pray for him. In addition, Paul uses his letter to talk about righteousness which comes from God.
Romans 11:33-36
"O the depth of the riches both of the wisdom and knowledge of God! how unsearchable are his judgments, and his ways past finding out! For who hath known the mind of the Lord? or who hath been his counsellor? Or who hath first given to him, and it shall be recompensed unto him again? For of him, and through him, and to him, are all things: to whom be glory for ever. Amen"