Irresponsible, shortsighted, rash and selfish conduct is often proof of immaturity. But we do not refer to years. People sixty and above may be immature - acting like little children when they do not get their way, or are forced to face the realities of this life. They are incapable of objectivity, their pride is easily hurt, and they throw a tantrum. That is bad enough in secular life, but it can be tragic in the church.
Bible knowledge maturity is found in those who dwell on something more than first principles (Hebrews ). They have learned that justice, mercy, and faith are the grounds upon which their concern for tithes of mint, anice and cummin can have validity. Ignore the first, and one becomes an hypocritical nit-picker with all else (Matthew -24). He may strain at a gnat, and swallow a camel.
People-dealing maturity comes only after we learn that we are all sinners (Romans ), and are completely humbled before God. The “babe” seeks an “issue” and perhaps make a “name” for himself. But maturity seeks for souls, hoping to “give ‘em Heaven,” and save them from Hell. The babe sees himself as a General in the Lord’s army; the mature saint is an expendable servant of the Lord.
Doctrinal maturity is not compromise with error. It is simply wisdom enough to know we do not know it all. The babe paddles wildly about on the surface of the water, loudly proclaiming his domination of the seas; but maturity is aware of the unexplored depths below. The fool has an answer, the wise, a reason.
Paul told Timothy to “flee youthful lusts” and “foolish and unlearned questions avoid” (2 Timothy ff). There is no “instant maturity” for any of us. We must start with instructions to youth, and “by reason of use” we may “grow up” in Christ. All of us are in the process in many facets of the Christian life, not having attained (Philippians ff). We can be patient and tolerant of blustering spiritual babes without appointing them as elders, preachers, and editors. In time, with enough milk and nurture, we may all learn to act like men.