To be a babe or not to be a babe? That is the question when it comes to spiritual maturity. The answer actually is both. In regards to believing faith, we are called to childlike. (see here) In regards to doing evil, childlike once again. But in regards to understanding and walking out our faith before God, we are called to maturity. (see here)
Our spiritual maturity can be most readily seen in our relationships. The Bible tells us that when there is jealousy and strife among us then we are acting like infants and “mere men”. (see here) In contrast those who have learned to “discern between good and evil” are counted as mature. (see here) They have learned through constant use how to know what is of God and what is not and can ultimately maintain the right attitude in their relationships because they want God’s blessing on their life and ministry.
Spiritual Maturity can also be seen in one who has grasped “the elementary principles of Christ” and can aptly teach them to others. (see here, here, and here) Since a person can never lead someone where they have not gone themselves, the missionary must have more than an occasional aquaintance with the Word of God. They must understand its message and implications for themselves and have taken it to heart and digested is contents for others to be nourished.
Missions work is for mature men and women of God who are childlike and not childish.