Now we know that whatever the law says, it says to those who are under the law, so that every mouth may be silenced and the whole world held accountable to God. Therefore no one will be declared righteous in God's sight by the works of the law; rather, through the law we become conscious of our sin. (Ro 3:9–20)

Read this portion of the verse:
through the law we become conscious of our sin. (Ro 3:9–20)

and read verse 2:13 again:
Ro 2:13. For it is not the hearers of the Law who are just before God, but the doers of the Law will be justified.
And now, understand. If we become conscious of sin, but do nothing about it, we are hearers of the Law and are not just before God.

But if we become conscious of our sin and repent, doing works meet for repentance (Acts 26:20), we are then doers of the law and we will be justified by God.

Ah, but there's more. How will we be justified by God? Scripture is clear:
Acts 22:16
And now why tarriest thou? arise, and be baptized, and wash away thysins, calling on the name of the Lord.
In Baptism:
Titus 3:5
Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost;So then, it is clear. Our works do not justify us. God does. But God does not justify those who do not, being conscious of their sin, repent and do works meet for repentance:
Revelation 22:14
Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.And that is the Catholic Teaching. Justification is by faith and works because only those who work to demonstrate their repentance will be justified.

Sincerely,

De Maria