What is your definition of maturity? When a child goes away to college? When a child leaves home and sets out on his own? When a child gets married? When a child becomes a parent?
Most likely your definition of maturity, like those above, will be based on a child’s attaining some level of independence from his parents. This is what our society, and probably most of those that preceded ours, have taught their children - that it is important to grow up, leave the nest and survive on their own.
It’s very interesting that earthly wisdom is so often in direct contradiction with heavenly wisdom. Earthly wisdom teaches that maturity is gained by becoming more and more independent of your parents. Heavenly wisdom teaches that maturity is gained by becoming more and more dependent on your heavenly Father.
When a person comes to faith, when he is born again of water and the Spirit, he is like a newborn baby. Indeed, not only does "born again" imply starting out as a baby, the Bible also draws an analogy of new Christians to "newborn babies" ("Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation." (1 Peter 2:2, NIV)).
Unfortunately, many people never "grow up"; that is, they never attain a level of maturity that is expected of someone their age. Likewise, many Christians never "grow up"; that is, they never learn to truly trust and depend on God. They go through life depending on their own abilities and pursuing their own goals and ambitions. They pay lip service to God on Sunday morning and occasionally Wednesday night, but only truly call on Him when circumstances spiral outside their control. As long as they can control things, they don’t grow as Christians but instead rely on themselves, on their own earthly maturity.
Many Christians don’t grow because they rarely "eat" ("So faith comes from hearing, and hearing through the word of Christ." (Romans 10:17, ESV)). Without regularly consuming the word of God, without praying regularly to God, without regularly practicing the words of God in their everyday life, they basically starve themselves and not only don’t grow as Christians but risk losing their faith entirely.
Just as parents desire for their children to grow up to be responsible, mature adults, so God also desires for us to grow up into responsible, mature Christians. As members of His body, the church, God has given each of us talents and gifts that we are to use as productive members of that body. However, our ability to be productive members of God’s church depends on our being responsible, mature Christians. Without growing into mature Christians, we are unable to fulfill the role that God has planned for us.
Another tidbit of earthly wisdom is that you are either growing or you are shrinking. Either you are becoming more responsible, more mature or you are becoming less responsible, less mature. This may be one case where earthly wisdom and heavenly wisdom coincide. If you are not growing as a Christian, you are probably shrinking. If your faith is not getting stronger, then it is probably weakening.
If you are not being a productive member of God’s church, and there are many ways to contribute, and if your faith and trust in God is not growing, then you are probably becoming a less mature Christian. This is a very risky path to be navigating.
While we can’t come to faith on our own (it is a gift from God), once the Holy Spirit has come to us and indwells us, we are responsible for our actions from that point forward. We can quench and grieve the Holy Spirit, we can pursue our own wishes, we can behave exactly as unbelievers behave or we can regularly honor, praise and glorify God by our words and actions, we can read, study and listen to God’s word, we can communicate regularly with God in prayer, we can attend church services faithfully, we can strive to lead holy lives, we can trust in God not just during trying times but also during good times.
We can either grow into mature, responsible, contributing Christians or we can remain children.