Children's are very cute, loving, faithful and harmless, they search for a smiling face to smile back and will return their best smile even to a smiling offender intending to harm them.
However as they grow up and start gaining wisdom they start sending out messages that now its hard to fool them, they are now well equipped to detect deceptive smiles, they can now easily recognize the craftiness behind the smiling faces.
"that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting, but, speaking the truth in love, may grow up in all things into Him who is the head—Christ—" Ephesians 4 : 14-15 (NKJV)
Paul wants believers to grow, he wants them to grow enough to reject any false doctrine and grow up to become like Christ.
God wants us to speak the truth, however in love and thus to grow in all things to be like Christ.
What is the truth? or rather can I rephrase it, "Who is the truth' ? Speak Christ to everyone, preach the gospel with and without words(through your life), let the world hear what God wants to tell them.
and let everything you do be out of love, for without true love we cannot win others for Christ, our words if not with love will not heal, will not encourage, will not accomplish God's will.
We will have many or less opportunities in life depending on the lifespan God has decided for us, however in everything we simply need the Truth and 'True love' and then we shall grow or else without the Truth and 'True love' we will shrink , we will be tossed around like children affected with ailments for when we should have grown, we did not and thus now this pitiable condition of ours.
"And you shall know the truth, and the truth shall make you free.” John 8:32 (NKJV)
Let's know Him, be free, make Him known and set others free and let this all be done in love, in the love of Christ, which faileth never.