"I wanna grow up and big, just like my Dad!"
A child often says this when he is young. Sometimes, he will put on their father's shoes, pick up (or rather drag) his suitcase and where his hat, then walk out the door.
After that, though, where does the child go?
In a similar way, Christians try to grow up in the Lord through their efforts, doing things that will please God or give the impression that they know what will please Him. They try to act in a mature fashion, wearing the right clothes, or saying the right words.
Yet just like the little child who stumbles along in his father's shoes, and cannot carry the briefcase, and the hat blinds his way, and he arrives at the threshold of his home with nowhere to go, so too everyone of us who tries to mature in Christ in our own efforts will find that our immaturity becomes more manifest.
So, how do we grow up?
We grow up as we grow in grace and knowledge of the Lord (2 Peter 3: 18)
"For by the grace of God I am what I am: and his grace which was bestowed upon me was not in vain; but I laboured more abundantly than they all: yet not I, but the grace of God which was with me." (1 Corinthians 15: 10)
Everything that we have, everything that we do, everything that we are is based on God's grace, which we receive through Christ:
"17For if by one man's offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ." (Romans 5: 17)
"To the praise of the glory of his grace, wherein he hath made us accepted in the beloved." (Ephesians 1: 6)
"Accepted" also means "graced" or favored.
"31Let all bitterness, and wrath, and anger, and clamour, and evil speaking, be put away from you, with all malice: 32And be ye kind one to another, tenderhearted, forgiving one another, even as God for Christ's sake hath forgiven you." (Ephesians 4: 31-32)