The word pneumatikos (πνευματικός) is used by NT writers to refer to divine revelation (Rom 7:14; 1 Cor 2:13-14; Col 1:9), demonic forces (Eph 6:12), blessings from God (Eph 1:3), a mental attitude of joy and worship (Eph 5:18-20; Col 3:16), our future glorified body (1 Cor 15:42-44), the church as a spiritual house (1 Pet 2:4-5), supernatural gifts from the Spirit (Rom 1:11; 1 Cor 12:1), spiritual sacrifices we offer to God (1 Pet 2:5b; cf., Rom 12:1-2; Eph 5:1-2; Phil 4:18; Heb 13:15-16), a mature believer who helps others (Gal 6:1), and is contrasted with immature carnal Christians (1 Cor 3:1-3). Concerning a definition of the word spiritual, there is no single verse in the Bible that defines it. Perhaps the closest verse on this subject is found in 1 Corinthians 2, where Paul wrote, “The unbeliever does not receive the things of the Spirit of God, for they are foolishness to him. And he cannot understand them, because they are spiritually discerned. The one who is spiritual discerns all things, yet he himself is understood by no one” (1 Cor 2:14-15 NET). However, in this passage, what we have is more of a description than a definition. Paul explains that unbelievers do not welcome what the Spirit offers and regard it as foolishness because they do not have the Spirit within them and are operating on negative volition. Being devoid of the Holy Spirit, it is impossible for unbelievers to discern the things that derive from the Spirit of God. In contrast, “one who is spiritual discerns all things” (1 Cor 2:15a). That is, Christians have a capacity to discern and welcome things that unbelievers cannot understand or welcome. Paul, in describing spiritual persons, contrasts them with immature Christians who are described as carnal and operating by their sinful natures (1 Cor 3:1-3). Because of this contrast by Paul between spiritual and carnal Christians, some Bible teachers regard spirituality as a state of maturity that is obtained over time. Charles Ryrie states at least three things make a person spiritual: regeneration, the work of God the Holy Spirit, and the passage of time.[1] If Ryrie is correct, spirituality would be a synonym for a mature Christian who knows God’s Word, is regularly yielded to God the Holy Spirit, and has advanced to a place of maturity by means of walking with the Lord over years of time. Ryrie takes this view, saying, “Spiritually is a mature and maturing relation to the Holy Spirit.”[2] He further states: "A new Christian cannot be called spiritual simply because he has not had sufficient time to grow and develop in Christian knowledge and experience. A new believer can be Spirit-controlled, but the area of control is subject to expansion in the normal process of Christian growth. A young Christian has not yet been confronted with many areas within the general sphere of Christian conduct, for instance; and while he may be completely willing to let the Spirit control his life and actions, he has not yet gained the experience and maturity that comes from having faced these problems and having made Spirit-controlled decisions about them. When he is first saved he may not even know that there is such a person as a weaker brother, and, although he may not be unwilling to curb his liberty for the sake of that brother, he has not yet faced the doing of it, to say nothing of having guided others into right decisions about such matters. Spirit-control may be total over the new Christian’s life insofar as he has knowledge of that life in his newborn state, but as his knowledge increases and his growth progresses, new vistas of life break upon him which must also be consciously yielded to God’s direction. Time to gain maturity is needed for genuine spirituality."[3] Wendell Johnston agrees, saying: "The fact that Paul used the figure of an infant to describe the Christians at Corinth helps us understand that spirituality is also a process, a matter of growth and development under the influence and control of the Holy Spirit. New believers can make proper decisions and often do because they yield to the Spirit’s control. However, the experiences of new believers, like those of infants, are limited. Time is needed for growth and development to face the challenges of the Christian life. Spirituality is a result of growth. Peter exhorted believers to rid themselves of actions that characterize unbelievers and to grow up in their salvation (1 Pet 2:1-2). In this passage he emphasized the role of the Word of God, which he called “spiritual milk” (1 Pet 2:2). The Scriptures provide the foundation for one’s walk with the Lord."[4] Based on this understanding, immature Christians cannot be called spiritual, as they don’t have enough knowledge of God and life experience as obedient-to-the-Word believers to live as He expects. Certainly, in at least one passage, the word spiritual seems to be used this way, as Paul wrote, ...
