Paul explains the difference between his view of salvation and that of his opponents (3:2).
Believers unite with Christ by trusting him for salvation and sharing in his life (see John 15:1–5).
We become righteous not by following the law of Moses, but through faith in Christ. This is God's way of making us right with him: Salvation is a free gift, not something we can earn (see Romans 1:17; 3:21–26; 4:5–8; Galatians 2:16; Ephesians 2:8–9).