God did it for us. Out of sheer generosity he put us in right standing with himself. A pure gift. He got us out of the mess we're in and restored us to where he always wanted us to be. And he did it by means of Jesus Christ.
They are justified freely by His grace through the redemption that is in Christ Jesus.
Romans 3:24 In-Context
This righteousness is given through faith in Jesus Christ to all who believe. There is no difference between Jew and Gentile,
for all have sinned and fall short of the glory of God,
and all are justified freely by his grace through the redemption that came by Christ Jesus.
God presented Christ as a sacrifice of atonement, through the shedding of his blood—to be received by faith. He did this to demonstrate his righteousness, because in his forbearance he had left the sins committed beforehand unpunished—
he did it to demonstrate his righteousness at the present time, so as to be just and the one who justifies those who have faith in Jesus.