When the New Testament addresses spiritual maturity, it uses the common Greek word teleios, which means “perfect” or “complete.” When it is applied to Christian growth, it indicates spiritual maturity in contrast to childlike immaturity as, for example, in this command from Paul: “Brothers, do not be children in your thinking. Be infants in evil, but in your thinking be mature (teleioi).” (1 Cor. 14:20; see also Heb.5:13–6:1). Sometimes it indicates perfection, as in Jesus’ summary command in the Sermon on the Mount: “You therefore must be perfect, as your heavenly father is perfect” (Matt.5:48). Spiritually, it always references solid, biblically informed understanding and conduct in Christ—spiritual adulthood.
Significantly, the job description for pastors is freighted with the responsibility of bringing the church to spiritual maturity, as stated in classic words to the church in Ephesus:
And he gave the apostles, the prophets, the evangelists, the shepherds and teachers, to equip the saints for the work of ministry, for the building up of the body of Christ, until all attain to the unity of faith and knowledge of the Son of God, to mature [teleion] manhood, to the measure of the stature of the fullness of Christ. (Eph. 4:11–13)
The question for all pastors and elders is How? Here, we suggest four essentials.
The first is preaching the mystery of Christ, as the Apostle Paul did for the Colossians, when he labored
to make the word of God fully known, the mystery hidden for ages and generations but now revealed to the saints . . . the mystery, which is Christ in you the hope of glory. Him we proclaim, warning everyone and teaching everyone with all wisdom, that we may present everyone mature [teleion] in Christ. (Col. 1:25a–28)
To proclaim the mystery of Christ is to preach the full canonical Christ. Christ-focused exposition progressively matures God’s people as they learn to see Christ in all of Scripture and to understand that the gospel is as old as the garden. Moreover, because Christ is “wisdom from God, righteousness and sanctification and redemption” (1 Cor. 1:30), Christ-focused exposition presents Him as the source and sustainer of spiritual maturity.
To effect maturity in their people, preachers must also struggle in preaching the mystery. What does it look like to have God powerfully working in you to proclaim Christ? Most would imagine something akin to the ease of omnipotence—just sitting back and watching God do it—going on autopilot and letting God fly around the homiletic pylons. Not so. The Apostle Paul himself agonized to proclaim the mystery—”For this I toil, struggling with all his energy that he powerfully works within me” (Col. 1:29). Surprising language. But there is a greater surprise, and that is that Paul, the faithful preacher, said that he struggles “with all [God’s] energy that [God] powerfully works within” him. Therefore, when God powerfully works within us preachers, we will struggle and agonize with all His energy.