We were never meant to stay spiritual babies. Babies cannot eat solid food or anything such as meat because they are not mature enough to physically digest. We as children of God are to grow up and mature in the knowledge, wisdom and our relationship with God but still not lose our child-like faith in Him.
Most Christians equate spiritual maturity to a stoic and staunch way of living. However, God's Word say something a little different. The Pharisees, Saducees and Scribes in Jesus' day where men who were considered the "spiritually mature" but Jesus didn't really give much credence to them or their maturity.
His qualifications of maturity differ quite a bit from the religious institution of His day and still do to many of the churches of today that bear His name. This week's teaching is about going from milk to meat and growing up in Christ.