What does 2 Corinthians 3:13 mean?
Paul has been comparing the glory of the old covenant between God and Israel and the new covenant of God's grace for all who come to Him through faith in Christ. The glory of the revelation of God through the old covenant was always fading away and being brought to an end. The glory of God's revelation of Himself through Christ is eternal. Through faith in Christ, God receives Jesus' death on the cross as payment for sin and gives credit for Jesus' sinless, righteous life in return.The result for him, Paul has written, is boldness and confidence while representing God to others. He has nothing to fear, because his standing before God is not based on his own performance. It is all based on Christ's righteousness.
Moses, on the other hand, could not be so bold in representing God to the Israelites. Paul is referencing Exodus 34. Moses returned to the people after being with God visibly changed in his appearance. His face reflected God's glory so powerfully that the people were afraid to come near him (Exodus 34:30). The glory of God was painful to them in their sinfulness. Moses covered his face to protect them from God's glory. He could not boldly reveal it to them as Paul revealed God's glory in the person of Jesus.