Ephesians 4:13-14

until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ.

(v13, NIV)

The building up of the body of Christ is a continual process. It continues until we all attain to the unity of the faith and of the knowledge of the Son of God. This means that this is the goal we should be striving for. We should strive to reach mature manhood and to the measure of the stature of the fullness of Christ. This is the kind of thing that we won't reach in this life. This growing and building up the body of Christ is a continual process.

Then we will no longer be infants, tossed back and forth by the waves, and blown here and there by every wind of teaching and by the cunning and craftiness of men in their deceitful scheming.

(v14, NIV)

This process of building up the body of Christ serves a purpose for each and every one of us. As we strive for the unity of faith and knowledge of the Son of God, it will produce in us a maturing and growing up. It says in verse 14 that we may no longer be children. Children are naive and are easily manipulated by every wind of doctrine. We shouldn't be easily swayed by every flimsy teaching we hear. We should learn to properly discern what is from God and what is not from God. The building up the body of Christ in this full process will help us to not be easily tossed to and fro by the waves.