Brothers and sisters, I could not address you as spiritual but as worldly—mere infants in Christ. I gave you milk, not solid food, for you were not yet ready for it. Indeed, you are still not ready. You are still worldly. For since there is jealousy and quarrelling among you, are you not worldly? Are you not acting like mere human beings? 1 Corinthians 3:1-3.
“There are different types of maturity. There is physical maturity (having a healthy, well-developed body), intellectual maturity (having a trained mind and a coherent worldview), moral maturity (referring to people ‘who have trained themselves to distinguish good from evil,’ Hebrews 5:14), and emotional maturity (having a balanced personality, able to establish relationships and assume responsibilities). But above all, there is spiritual maturity. What is that? Well, the apostle calls it maturity ‘in Christ,’ that is, having a mature relationship with Christ. To be ‘in Christ’ is to be personally, vitally, organically related to him. In this sense, to be mature is to have a mature relationship with Christ in which we worship, trust, love and obey him.” – John Stott.