*Baby Christians are jealous. In I Corinthians 3, Paul addresses the church as "mere infants in Christ," people who are not ready for spiritual "meat." He indicates that a symptom of immature faith is jealousy and quarreling. Babies are self-centered. They know no other way. Likewise, an immature believer is consumed with self. If you constantly find yourself to be jealous of others or overly concerned with the affairs of other believers, you have a pride and jealousy issue. You want what others have because you feel you deserve what others have. My niece and nephew (4 and 2 respectively) can go from sweet to very quickly at each other's throats when something they both want enters the scenario. This is normal for toddlers...it's not okay for supposedly mature Christians.
*Baby Christians are unskilled with God's Word. Paul indicates in Hebrews 5:13 that spiritual babies are unable to rightly divide God's Word. Want to know if you're spiritually mature? Ask yourself, "How well do I know God's Word? How often do I read His Word?" Further, do you simply read God's Word or do you study it, breathing it in like oxygen needed to survive? Your spiritual maturity is completely dependent on your study of God's Word. Unfortunately, there are many Biblically illiterate Christians who consider themselves mature. This is nearly impossible.
*Baby Christians have no discernment between good and evil. Again, in Hebrews 5, Paul notes that spiritual babies cannot rightly determine between right and wrong. Young children have to be taught from birth what is right and wrong. They have little natural discernment about good and evil. As Christians, we often think we know right from wrong when the truth is we're either misguided or afraid to stand for what's right. I believe that the term "gray area" has probably been used more over the last two decades of Christendom than the previous 1900+ years combined. What has always been considered right and always been considered wrong is now up for grabs in a post-modern culture that throws absolutes to the wind. Spiritually mature people do not lose their moral or Biblical compass. Do not misunderstand what I mean here. I'm the last person to insist that a movie with an "R" rating or a "secular" song is evil. These labels are oftentimes unfair and lead to Christians who can't/don't think for themselves. We need to judge all things on merit, not on label. Yet, there are many things that the Bible is clear are wrong and yet, we have made them gray areas. The spiritually mature person knows what the Bible teaches and is not afraid to stand up for what's right. A spiritually mature person does not consistently take the "gray area" route to avoid offense or to avoid making a hard call in their own life. Spiritually mature people are not tossed to and fro by the cultural and community waves.
*Baby Christians have no filter on their words. You may remember Bill Cosby's program "Kids Say the Darndest Things." Bill would interview children and, just like the title indicated, they would say outrageous, unscripted things. Kids have a tendency to simply blurt out what they think and what is in their heart. Sometimes that makes you feel good when it's nice, and sometimes you learn some thing about yourself that you didn't want to know! Spiritually immature people are similar to children in that they do not filter their words. The New Testament talks at length about how a Christian should talk. Scripture not only outlines what is evil (gossip, slander, coarse joking, inappropriate language) but also gives guidelines for what we SHOULD be saying (encouragement, prayer, praise, etc). Jesus said that out of the abundance of the heart the man speaks/acts. You can almost always tell if a person is spiritually mature by the way they speak to and of others. If your words are full of hate, envy, discouragement and destruction, you'll have a hard time convincing me that you are not a spiritual baby. In fact, you may have a hard time convincing anyone that you are a believer at all.
*Baby Christians can't feed themselves. Paul wrote in Hebrews that there were Christians who should have been mature enough to teach and yet they were still being bottle-fed milk. This may be the biggest but most subtle symptom of baby Christianity. I can't tell you how many times I have whined after a Church service that I didn't "get anything" out of the sermon. Those are the words of a spiritually immature person. Once you consider yourself to be spiritually mature, the emphasis shifts from being discipled to being a discipler. You still must feed yourself on God's Word, and the Bible is rich and filling to those who hunger for it. However, you begin to approach "church" and "sermons" as an opportunity for others to be fed and for yourself to gain tools to feed others. This is something that has strongly convicted me recently and is changing my approach to church.
I don't have everything figured it out. However, that does not undermine my message here or knock me off my soap box. I acknowledge my failings and desire to grow more mature in my faith, and these are two key ingredients for growth----humility and desire. I hope to see God glorified through my life and through the lives of those around me. If we stay infants forever, we limit the good we can do for the sake of Christ. Babies can only do so much, and babies are a lot of work for those who are mature. Let us grow up into the strength, power and wisdom that is part of the inheritance promised to us in Christ. It's time to get off the bottle.