What does Ephesians 4:13 mean?
Church leaders are to equip believers to serve, in order to build up the community of believers (Ephesians 4:12). This verse adds three additional reasons. First, Paul wants believers to live in unity. This unity is based on the essentials of our faith. It does not imply compromising necessary beliefs, or a lack of beliefs.Second, believers are to grow in "knowledge of the Son of God." The focus of church leaders is preparing Christians to serve others, in practical ways. And yet, knowledge is a critically important part of effective service.
Third, Paul wants every believer to grow in maturity. Obviously, Paul is not referring to biology. Instead, he means spiritual growth, which includes increases in the fruit of the Spirit (Galatians 5:22–23) and our love for both God and others (Matthew 22:37–40). The end goal is to be "full" of Christ or the "fullness of Christ" (also Ephesians 1:23: 3:19). Paul often wrote of the importance of maturity for believers (1 Corinthians 2:6; 14:20; Philippians 3:15; Colossians 1:28; 4:12). Hebrews 5:14 adds that "solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil."