Why do we need the Gospel?
Paul details the need that humanity has for the Gospel by showing the progression of sin among mankind and the wrath of God that is being poured out on them. Paul describes this wrath as God letting mankind have what they are showing they want; a godless existence. Those who do not repent from this desire will ultimately again be given what they have asked for; a godless eternity. Paul's goal here to also to show the Jews that they are headed to the same future unless they place their faith in Jesus Christ as well.