After a long discussion about the power of sin (1:18–3:20), Paul returns to the main idea in 1:17, which is how to be in a right relationship with God (literally the righteousness of God). In 1:17, “the righteousness of God” is the way that God puts people in right relationship with himself.
apart from the law: The old covenant looked ahead to God’s righteousness being revealed in his Son, Jesus Christ. Through Christ, God fulfilled the law for us. Because of what God has accomplished for us in Christ by completely fulfilling the requirements of the law, we are now able to come to him by faith, apart from the covenant structure set up by the law of Moses (see Hebrews 8:13).