1 Corinthians 3:1

1 Corinthians 2:14-15 NIV
The person without the Spirit does not accept the things that come from the Spirit of God but considers them foolishness, and cannot understand them because they are discerned only through the Spirit. The person with the Spirit makes judgments about all things, but such a person is not subject to merely human judgments,

Ephesians 4:13-14 NIV
until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ. Then we will no longer be infants, tossed back and forth by the waves, and blown here and there by every wind of teaching and by the cunning and craftiness of people in their deceitful scheming.

Hebrews 5:13 NIV
Anyone who lives on milk, being still an infant, is not acquainted with the teaching about righteousness.