For all who are led by the Spirit of God are sons of God (Romans 8:14 Amplified Bible).
Sons (that is, mature sons and daughters) and children both belong to the Father. However, sons strive to be led by His Spirit in all that they do, even when such leading is unpleasant to their flesh. Children, on the other hand, are full of their own ideas and opinions, and love to do their own thing.
Many in our world today belong to our heavenly Father, having been reconciled with Him through His Son Jesus Christ. However, many who belong to His kingdom are yet children. God delights in His children but desires them to grow into mature sons and daughters. Why is spiritual maturity so important? Because the purposes of God are best served by mature Christians. The Bible, in Galatians 4:1, tells us that “the heir, as long as he is a child, does not differ at all from a slave, though he is master of all.” The Lord Jesus Christ also alluded to the weakness associated with remaining a spiritual child when, in speaking about the great tribulation, He said, “But woe to those who are pregnant and to those who are nursing babies in those days!” (Matthew 24:19) Our Lord’s words were not a curse, but an indication of how difficult it will be for spiritual babies to survive the conditions of the great tribulation.
We are in the end time, and the conditions in the world in which we live are so harsh that it takes spiritual muscle and maturity to overcome. But the body of Christ is relatively weak, and that's because there are more spiritual children than there should be in her midst. Ideally, Christians who are born into the kingdom of God as babies should grow up and help to build others and to uphold the deeper purposes of God; there should not be a disproportionate weighting of believers toward the lower end of the maturity spectrum.
Of course, spiritual maturity is not about dedication to one’s denomination or commitment to church events—even though mature Christians do tend to be more committed. Spiritual maturity is about growth in a believer’s relationship with God. Such growth comes through on-going personal fellowship with the Father, obedience to His Word and Spirit, and corporate worship (prayer, fasting, study of the Word, etc.) with believers who are like-minded. Indeed, as we mature through the exercise of these disciplines, we develop a devotion to God’s service and to the groups with whom we share fellowship. Such devotion is not born out of a desire to please human beings, but out of a love for God and a desire to serve His purposes. We also develop a love for the body of Christ in a broader sense, as we observe God's love for her and respond to His commandment to love one another .
The Church of Jesus Christ needs many more believers who are willing to grow into maturity. Will you do your part of waiting on the Lord, surrendering your all to Him, and allowing Him to build you up into a mature and effective member of the body of Christ?