Therefore you shall be perfect, just as your Father in heaven is perfect. (Matthew 5:48)
1 Corinthians 2:6 and 1 Corinthians 3:1-3 illustrate teleios in a contrast.
However, we speak wisdom among those who are mature, yet not the wisdom of this age, nor the rulers of this age, who are coming to nothing. (1 Corinthians 2:6, emphasis added to show teleios in the passage)
The mature Christian can speak and listen to godly wisdom. The mature Christian can teach and instruct in wisdom and also listen to and learn in wisdom. Wisdom would include knowledge and understanding, with how to apply that knowledge to our lives. If you are immature in Christ you will find it difficult to recognize God’s wisdom or understand it when faced with it. I personally want wisdom and pray for it daily (James 1:5). Teleios, or maturity, has great benefits including the use of God’s wisdom to make decisions and to live according to His Word.
The passage above warns against the wisdom of this age and those who lead with worldly wisdom as their guide. Know God’s Word. Grow and mature in Him by the Holy Spirit. If you need help discerning godly wisdom from worldly wisdom see James 3:13-17.
And I, brethren, could not speak to you as spiritual people but as to carnal, as to babes in Christ. I fed you with milk and not with solid food; for until now you were not able to receive it, and even now you are still not able; for you are still carnal. For where there are envy, strife, and divisions among you, are you not carnal and behaving like mere men? (1 Corinthians 3:1-3 emphasis added)
What does this passage tell us of the babes, or the immature?
They are not spiritual, but carnal. Carnal is fleshly or worldly. As the baby cries for what it wants to satisfy itself as babe in Christ is still self-oriented and thinking only of its desires. Maturity brings you from being worldly to being heavenly, or spiritual, in both actions and understanding. A spiritual person is led by the Holy Spirit and the worldly person is led by the desires of his flesh, or the desires devoid of the Holy Spirit.
The immature eats milk, not solid food. Milk, to baby food, to solid food: this is the picture of progression in how children learn to eat. The same applies to the maturing Christian. What is your understanding of Scripture? Do you want to learn? Do you want to go deeper into God’s Word? Or do you just want the basics being given to you time and time again?
Envy, strife, and divisions exist. This is a difficult standard to measure against because envy strife, and divisions are often perpetrated by those who claim to be smarter than others. It is often hard to determine who causes these actions. That is why in real life it is the reconciliation efforts that determines who is mature and who is not. Stuff happens in the fallen world in which we live. Are desire to fix the fractures to community often indicate growth and maturity.
Acts like men (the world). Some self-evaluation is needed here. Are you using the methods of the world? Are you worldly or spiritual? What motivates you? Why do you make the choices you do? What choices do you make? Choices should be made with godly wisdom (see above) and be influenced by the direction of the Holy Spirit. The mature relies upon the Spirit’s guidance in decision making and prays for godly wisdom. How do you approach life?
The Scripture is clear that growth for the Christian is the normal way of life. Do not let the speed bumps along the path deter you from growing down the road to immaturity.