Now, truthfully in love, grow up in all, to the extent of him, the one who is the head, Christ (Ephesians 4:15)
The word truthfully means come true, be realized, be true, be right; prove to be true. We see its meaning in the verse's context, truthfully in love we grow up in knowledge of Jesus, Ephesians 4:15, into mature adulthood, into the full measure of his image. Jesus is the word of God, the truth, thus we grow up in knowledge of Him, the head, like seeds in a sunflower. This word of truth is the gospel of our salvation and our salvation encompasses spirit, soul, and body, so we are to abide in the truth to know the truth, and be set free by it. It is continuing in truth that knowing or being proven to be true or mature is realized. With truth being realized, with growth in the truth, children of God become mature.
so that we are no longer children tossed and blown about by winds of doctrine in human cunning, that in craftiness with deceitful scheming, but truthfully in love grow up... (Ephesians 4:14-15)
Why are gifts given to the church? So that children grow up into maturity. This implies a child can not discern nor be obedient to God's will. Without transformation, the renewal of the mind, they will not approve of truth in regards to having the ability to practice, to accept it as good and pleasing. A church can grow in many ways without being in truth, but without truth being realized, you just have children. If we are not mature when the storms in this life come, the foundation will be revealed, and great is the fall of the house not built on the Rock, the words of Jesus, the truth. Thus truthful in love we grow up.
That person is not holding fast to the head, from whom the whole body, nourished and held together by its joints and ligaments, grows with a growth that is from God (Colossians 2:19)
How do we grow? How does the church grow? holding fast to the head, who is Christ. We are to put away childish things (1 Corinthians 13; 1 Peter 2:1) and "like newborn babes, crave the milk that is pure and spiritual, so that by it you may grow up to salvation" (1 Peter 2:2). What are the signs of growth? "... your faith is growing abundantly, and the love of each one of you for one another is increasing" (2 Thessalonians 1:3). Truthfully in love the church grows. Faith is growing because of truth and love is the bond that leads to maturity (Colossians 3:14).