The most simple truths of the gospel, as to man's sinfulness and God's mercy, repentance towards God, and faith in our Lord Jesus Christ, stated in the plainest language, suit the people better than deeper mysteries. Men may have much doctrinal knowledge, yet be mere beginners in the life of faith and experience. Contentions and quarrels about religion are sad evidences of carnality. True religion makes men peaceable, not contentious. But it is to be lamented, that many who should walk as Christians, live and act too much like other men. Many professors, and preachers also, show themselves to be yet carnal, by vain-glorious strife, eagerness for dispute, and readiness to despise and speak evil of others.
20 Brethren, be not children in understanding: howbeit in malice be ye children, but in understanding be men. men: Gr. perfect, or, of a ripe age
English Standard Version
20 Brothers, do not be children in your thinking. Be infants in evil, but in your thinking be mature.
20 To be perfectly frank, I'm getting exasperated with your infantile thinking. How long before you grow up and use your head - your adult head? It's all right to have a childlike unfamiliarity with evil; a simple no is all that's needed there. But there's far more to saying yes to something. Only mature and well-exercised intelligence can save you from falling into gullibility.
New King James Version
20 Brethren, do not be children in understanding; however, in malice be babes, but in understanding be mature.
New Living Translation
20 Dear brothers and sisters, don't be childish in your understanding of these things. Be innocent as babies when it comes to evil, but be mature in understanding matters of this kind.
There can be no assent to prayers that are not understood. A truly Christian minister will seek much more to do spiritual good to men's souls, than to get the greatest applause to himself. This is proving himself the servant of Christ. Children are apt to be struck with novelty; but do not act like them. Christians should be like children, void of guile and malice; yet they should not be unskilful as to the word of righteousness, but only as to the arts of mischief. It is a proof that a people are forsaken of God, when he gives them up to the rule of those who teach them to worship in another language. They can never be benefitted by such teaching. Yet thus the preachers did who delivered their instructions in an unknown tongue. Would it not make Christianity ridiculous to a heathen, to hear the ministers pray or preach in a language which neither he nor the assembly understood? But if those who minister, plainly interpret Scripture, or preach the great truths and rules of the gospel, a heathen or unlearned person might become a convert to Christianity. His conscience might be touched, the secrets of his heart might be revealed to him, and so he might be brought to confess his guilt, and to own that God was present in the assembly. Scripture truth, plainly and duly taught, has a wonderful power to awaken the conscience and touch the heart.