The term spiritual translates the Greek adjective πνευματικός pneumatikos, which is applied to Christians in a few New Testament passages (1 Cor 2:15, 3:1; 14:37; Gal 6:1). The Christian who is called spiritual (1 Cor 2:15) is contrasted with the natural man (ψυχικός psuchikos), who is unsaved, having no spiritual life (1 Pet 1:3, 23), and is “devoid of the Spirit” (Jude 1:19). Furthermore, the spiritual Christian is contrasted with immature believers who are called “infants in Christ” (1 Cor 3:1), regularly governed by their sin natures, called “fleshly” (1 Cor 3:3a) and who live “like unbelievers” (1 Cor 3:3b CSB). Spiritual Christians are mature in their knowledge of God’s Word (1 Cor 2:6; 14:20; Heb 5:12-14), and regularly manifest the fruit of the Spirit (Gal 5:22-23). According to Charles Ryrie, “In 1 Corinthians 2:15 we have the nearest thing to a definition of spirituality, and that is actually only a description. If the spiritual believer judges or examines or discerns all things, yet himself is not understood by others, then spirituality means a mature, yet maturing, relationship to God.” And William Evans states:
- "The biblical concept of a spiritual Christian is one who is governed by the Holy Spirit rather than by his lower nature. “He that is spiritual” is contrasted with “the natural man,” that is, the soulish or unregenerate individual (1 Cor 2:14-16). The spiritual person is also set over against the carnal or fleshly believer who is still a babe in Christ (1 Cor 3:1-4). Christians are exhorted to grow by feeding on the Word (1 Pet 2:2). The Holy Spirit teaches them by means of the Scriptures (John 16:13). They are led by the Spirit (Rom 8:14); walk in the Spirit (Gal 5:16); bear spiritual fruit (Gal 5:22-23); are strengthened by the Spirit (Eph 3:16); and are filled with the Spirit (Eph 5:18)."
Assuming new life and an advance to spiritual maturity, the Christian will not attain sinless perfection in this life. According to Charles Swindoll “Christians will not attain perfect Christlike maturity in this earthly life. Yet they can grow enough through sanctification to become characterized as ‘spiritual’ or ‘mature in Christ.’ The apostle Paul denied that he was perfect, but he was certainly mature and was aggressively pursuing further growth in Christ (Phil 3:12–14).”
Spirituality is the life the Christian enjoys when properly living in dependence upon the Holy Spirit and walking according to Scripture. This advance assumes one has believed in Christ as Savior and has spiritual life (John 3:16; 6:28-29; 20:31; Acts 4:12; Rom 5:6-10; Eph 2:8-9; Tit 3:5; 1 Pet 1:3, 23). Salvation is by grace alone, through faith alone, in Christ alone. Only Christ’s atoning work on the cross is sufficient to satisfy God’s righteous demands toward our sin (1 John 2:2). No works are necessary for us to be saved. We need only Christ. When the Philippian Jailer asked the apostle Paul, “What must I do to be saved?” (Acts 16:30). Paul replied, “Believe in the Lord Jesus, and you will be saved” (Acts 16:31). Believing in Christ means we trust Him to do for us that which we cannot do for ourselves; to save us. It means we trust solely in Him and nothing more. Though good works should follow our salvation, they are never the condition of it.
Once we are born again, God desires that we advance to spiritual maturity, which glorifies Him and blesses us and others. The information taught in this lesson applies only to the Christian, for “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” (1 Cor 2:14 NET; cf. John 8:43-44).
The advance to spiritual maturity is a process that takes time as Christians learn and live God’s Word on a regular basis. There is always opposition, for we live in a fallen world and are confronted with many obstacles and distractions that seek to push or pull us away from God. Though constant distractions are all around us, we move forward by “destroying speculations and every lofty thing raised up against the knowledge of God, and are taking every thought captive to the obedience of Christ” (2 Cor 10:5). Bringing our thoughts into captivity means focusing our minds on God and His Word (Isa 26:3; Prov 3:5-6; 2 Cor 10:5; Col 3:1-2), and not allowing our thoughts to be bogged down and trapped with the cares of this world (Matt 6:25-34).
 Charles Caldwell Ryrie, Basic Theology: A Popular Systematic Guide to Understanding Biblical Truth (Chicago, IL: Moody Press, 1999), 433.
 William Evans and S. Maxwell Coder, The Great Doctrines of the Bible, Enl. ed. (Chicago: Moody Press, 1974), 316–317.
 Charles R. Swindoll and Roy B. Zuck, Understanding Christian Theology (Nashville, TN: Thomas Nelson Publishers, 2003), 951.