Romans 3:21-26 But now the righteousness of God has been manifested apart from the law, although the Law and the Prophets bear witness to it— 22 the righteousness of God through faith in Jesus Christ for all who believe. For there is no distinction: for all have sinned and fall short of the glory of God, 24 and are justified by his grace as a gift, through the redemption that is in Christ Jesus, 25 whom God put forward as a propitiation by his blood, to be received by faith. This was to show God's righteousness, because in his divine forbearance he had passed over former sins. 26 It was to show his righteousness at the present time, so that he might be just and the justifier of the one who has faith in Jesus.
Romans 3 speaks in very general terms of the state of man before the coming of Christ. According to Romans 3:11-16 "There is none that understandeth, there is none that seeketh after God", "there is none that doth good", "The venom of asps is under their lips", "Their feet swift to shed blood", etc.
Whom did Mary murder?
Besides, the entire passage is a quote from Psalms 13 (in your numbering 14), but the scripture also contains the next psalm that speaks of righteous people.
Read the scripture with attention and you will begin to understand it and you will become Catholic, and learn to love it.