These words have in common that they all denote the very young child. Brephos is an unborn child, Luke 1. 41, a babe new-born, Acts 7. 19, and a child still in babyhood. So then the children brought to Christ, Luke 18. 15, included the very young, and Timothy’s instruction in the Scriptures evidently began at the very earliest moment, 2 Tim. 3. 15. The word is not used in the New Testament in any derogatory sense. Peter does not chide his readers for being like new-born babes, though he docs remind them that they should desire their spiritual milk ‘that they may grow thereby unto salvation’, 1 Pet. 2.2 (r.v.), for there are things from which we cannot be saved unless we grow.
Teknion, ‘little bairn’, a diminutive of teknon, similarly denotes the very young (cf. Gal. 4.19). In the New Testament it is used solely as an affectionate form of address by Christ to the apostles, John 13. 33, or by the apostles to their spiritual children. In his first epistle John thus addresses all his readers, though they included some who were spiritually mature, fathers, 1 John 2. 13, 14.
Paidion, too is a diminutive and is used to denote a very young child, e.g., Matt. 2. 8, or a child as distinct from an adult. When used in reference to an adult it can have a derogatory sense, as when Christ reproached the Jews for adopting a childish attitude, Luke 7. 32, or it can be used in an affectionate sense as by Christ in resurrection ‘Children, have you anything to cat?’, John 21. 5, and the apostle John, 1 John 2. 18.
Nepios literally means infant, i.e., one who cannot yet speak, though in Homer it is extended to cover those not yet able to bear arms and in legal contexts it means a minor. This latter is presumably the intended meaning in Galatians 4. 1, ‘As long as the heir is a minor …’ where Paul is describing the state of even godly Jews before the coming of God’s Son into the world. They were minors and little better than slaves.
In the figurative sense the state of a nepios is not in itself morally wrong. The description of the apostles as babes, Matt. 11. 25, was not meant to cast a slur upon them; it merely contrasted them with men who had had greater opportunities for education and learning, but who unfortunately had become proud in the imagined self-sufficiency of their intellects. But to remain a nepios when both time and opportunity have come to put away childish things is certainly blameworthy. It is helpful to notice what are some of the causes and marks of spiritual childishness. We learn from 1 Corinthians 3. 1 that it is spiritual immaturity to be so impressed by and attached to a servant of God as to put him virtually in God’s place, v. 5-6, or to be ‘puffed up for him against another’, ch. 4. v. 6; from Galatians 4. 1 that it is a return to childhood to go back to the Law and its ceremonies for salvation; from Ephesians 4.14 that it is a mark of the immature that they are too easily impressed by any and every new-fangled idea and in consequence never know what they really believe and have no firm hold on the fundamentals of the faith; from Hebrews 5. 11-14 that immaturity is prolonged by a culpable neglect to exercise one’s powers of discernment in the reading of Scripture and results, among other things, in being unable to understand the Old Testament types; and from 1 Corinthians 13. 11-13 and 14, 20 ff., that the mature person will perceive the far greater value of genuine, practical love, compared with the pursuit of the ‘miraculous’ for its own sake, quite apart from the consideration of its moral or spiritual benefit.