Hebrews 6:1-8 (ESV)
Therefore let us leave the elementary doctrine of Christ and go on to maturity, not laying again a foundation of repentance from dead works and of faith toward God,  and of instruction about washings, the laying on of hands, the resurrection of the dead, and eternal judgment.  And this we will do if God permits.  For it is impossible to restore again to repentance those who have once been enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit,  and have tasted the goodness of the word of God and the powers of the age to come,  if they then fall away, since they are crucifying once again the Son of God to their own harm and holding him up to contempt.  For land that has drunk the rain that often falls on it, and produces a crop useful to those for whose sake it is cultivated, receives a blessing from God.  But if it bears thorns and thistles, it is worthless and near to being cursed, and its end is to be burned.
A real believer in Jesus Christ will never be content with his current state of knowledge of the doctrines of the faith. The more one studies the Scriptures, the more one has a hunger fed for more.
The Bible is an amazing Book. One can read it on the day he is saved and understand what he reds and get started on a journey of knowing more. Years later the very same text that was understood so simply will be read again and theological depths will be mined out of it that no new Christian would be able to make any sense of.
When the writer to the Hebrews tells his readers that they need to go on to maturity, he is not for a second suggesting that they move away from the Scriptures to better and deeper things. He is telling them to plumb the Scriptures with greater understanding. The Book that God has given us can challenge all saints, no matter how intelligent they are or how well versed in the doctrines of the faith. They can also feed the most simple Christian and enable the most feeble minded to live a life pleasing to God.
There is however, a subtle danger in the truth that great things not seen before can be mined out of the Scriptures. Many Christians are enamoured with the spectacular and the mysterious. There is a fascination with “secrets” that only a few people know.
A few years ago finding secret messages encoded in the texts of Scripture was all the rage. It sounded deep, mysterious, requiring special knowledge that not all possess to cipher the codes contained in the Bible about current events. This is not maturity. It is nonsense and truly mature Christians will flee from it as fast as they can.
Then there are the teachings that claim to reveal signs of the coming of Christ, the identity of the AntiChrist, the date of the end of the world. There seems to be no end to “secrets” in the Scriptures that only the author of some book knows and that you can discover if you buy the book. Whether the motives behind such things are monetary gain, power, popularity or just the machinations of a convoluted mind, they are to be avoided. They are such things as we are warned about in Ephesians 4:13-14; I Timothy 1:6-7; I Timothy 4:7; II Timothy 3:1-5; II Peter 3:16; Jude 4.
So, the writer to the Hebrews wants us to grow up in the faith and be able to handle the deep truths of the Scriptures, but that does not mean that we are to allow the wool to be pulled over our eyes by seemingly wise teachers who are wolves in sheep’s clothing.
Grow up, but do not grow away from the cardinal truths of the faith.