The world is made up of different types, or groups, of people. One such group is that of believers, however, within this group there is another division, those who are infants and those who have gone on to maturity.
Take a look at Hebrews 5:11–6:3
“We have much to say about this, but it is hard to explain because you are slow to learn. In fact, though by this time you ought to be teachers, you need someone to teach you the elementary truths of God’s word all over again. You need milk, not solid food! Anyone who lives on milk, being still an infant, is not acquainted with the teaching about righteousness. But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil.
Therefore let us leave the elementary teachings about Christ and go on to maturity, not laying again the foundation of repentance from acts that lead to death, and of faith in God, instruction about baptisms, the laying on of hands, the resurrection of the dead, and eternal judgment. And God permitting, we will do so.”
So what are the differences between spiritual infants and those who are spiritually mature?
INFANTS: They drink milk – the elementary truths of God’s word – repentance from acts that lead to death, faith in God, instruction about baptism, the laying on of hands, resurrection of the dead, and eternal judgment (Heb 6:1-2). Infants are not acquainted with the teachings about righteousness (Heb 5:13)
THE MATURE: They eat solid food, and have been trained to distinguish good from evil (Heb 5:14).
Doesn’t this seem a little strange? Most people think they can easily distinguish good from evil, right? Yet the elementary teachings, the ‘milk’, include things like resurrection of the dead, and eternal judgment, things that not many people understand or are able to clearly explain. What is the first resurrection? What is the second resurrection? What is the lake of fire, the second death? And what then is the first death? How can we claim to be mature, able to distinguish good from evil, if we do not understand even the elementary truths of God’s word?
Romans 10:1-2 says that the Israelites were very zealous for God, but that their zeal was not based on knowledge. The next verse says that since they did not know the righteousness that comes from God, they did not submit to it, instead they sought to establish their own. This shows their spiritual infancy – not being acquainted with God’s righteousness. And since their zeal was not based on knowledge we can see that it is still possible to have faith and actions even without the correct knowledge and understanding of God’s word.
We have to seek God’s righteousness, instead of establishing our own and creating our own understanding. We must not be like the zealous Israelites who lacked knowledge and so remained in spiritual infancy. We have to go on to maturity.
Check out this great article: Moving from elementary to mature faith, by 1of144000.org