That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive; Ephesians 4:14
God's desire and intent for each of His children is that we should grow up spiritually. This is not something that just happens over time just because we are saved. It also is not something we can make happen in our own effort.
From v.11 of this same chapter, we see that God provided pastors and teachers for the perfecting and edification of the saints. And in 1 Peter 2:2, we find, "As newborn babes, desire the sincere milk of the word, that ye may grow thereby:" So, we have pastors and teachers to teach us the Word of God so that we might grow up.
Then, we find in John 14:26, "But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you." We have been given the Holy Spirit to teach us. Nothing will be gained by reading the Bible without the work of the Holy Spirit to reveal the truth to our hearts. This is why unbelievers cannot understand the Bible. They lack the Holy Spirit.
And finally, we need faith. In Hebrews 11:3, we read "Through faith we understand that the worlds were framed by the word of God, so that things which are seen were not made of things which do appear." The key part of this verse is "Through faith we understand." Again, the Bible does not make sense to the unbelieving mind.
Growing, or maturing, as is the real meaning of the word "perfect" in scripture, requires only that we study God's Word and allow the Holy Spirit to reveal truth to our hearts. By faith we receive what He reveals to us, and He works maturity in us. As we get started, we take in the "milk," things that are simpler and more on the surface. As we mature, we take in the meatier things that require some chewing. Hebrews 5:14 "But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil."
Maturing implies increasing in knowledge, understanding, wisdom and character. Spiritually, this can only be accomplished as mentioned above. There is nothing else in this world that can bring about spiritual maturity in our lives. The world will talk about spirituality, and writes many books on the subject that explain how to become "spiritual." Their idea is some man made spirituality where they attempt to act a certain way and call that spirituality. It is simply empty attempts that lead to nowhere.
So, what is the purpose of spiritual growth and maturity? Is there any value in this pursuit? Why would we spend our time studying the Bible and praying? In Ephesians, we find this in the context of walking worthy and bringing glory to God. There is eternal value. Those that aspire to bring God glory, will desire to come to spiritual maturity.