'Milk' in the Bible

I fed you milk, not solid food, for you were not yet ready. In fact, you are still not ready,

Who ever serves in the army at his own expense? Who plants a vineyard and does not eat its fruit? Who tends a flock and does not consume its milk?

For though you should in fact be teachers by this time, you need someone to teach you the beginning elements of God's utterances. You have gone back to needing milk, not solid food.

For everyone who lives on milk is inexperienced in the message of righteousness, because he is an infant.

And yearn like newborn infants for pure, spiritual milk, so that by it you may grow up to salvation,