1 Peter 2:2 is a good place to start. "Like newborn babies, long for the pure milk of the Word, so that by it you may grow in respect to salvation.” Peter is using the illustration of a baby to describe a reality in the lives of the disciples. We intuitively know what he is writing about when he describes the “longing” that babies do for milk. Believe me, as one of the fathers of the newborns, I know that there is no doubt when a baby longs for milk. Especially at 2:37 AM. Through their crying, babies are saying, “I NEED MILK!!!!!!” Though they can’t speak, they are saying, “I think I won’t live unless I have this milk!!” That is true. Without that milk, they will not live. Christians will not live spiritually without the “pure milk of the Word.”
During my growing up years I loved to guzzle milk. Okay, I still love to guzzle milk. We’ve heard the slogans: “Milk. It does a body good.” and “Drink milk for strong bones.” Milk helps us grow. The parallel between physical milk and the milk of God’s Word is identical in this regard as well. In Ephesians 4:15, the Apostle Paul states, "Rather, speaking the truth in love, we are to grow up in every way into Him who is the head, into Christ.” As we feed on the milk of God’s Word, He brings growth into our lives. We grow into Christ.
In addition to the positive illustration of growing strong, there is a negative connotation connected to milk and babies in Scripture. Read this warning in Hebrews 5:12-14. “For though by this time you ought to be teachers, you need someone to teach you again the basic principles of the oracles of God. You need milk, not solid food, for everyone who lives on milk is unskilled in the word of righteousness, since he is a child. But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil.” Someone who drinks milk and never learns to eat meat is an overgrown baby. These “Baby Huey” Christians are content to drink milk. Milk is good, yes. But Scripture invites us to feast on the “solid food” that Scripture offers as well.