The Lord and his apostles spoke of spirit but today we fail to understand what they meant. In the time of Jesus, we see from Plato’s Republic that there was a tripartite model of human beings which was physical, mental, and spiritual natures. Peter wrote of extending one’s faith by improving one’s virtue, knowledge, self-control, perseverance, godliness, brother.y kindness, and love. These qualities are really one’s spiritual qualities, because they tend to come from our spiritual nature, which Plato had described as the seat of nobler qualities and will. To grow in knowledge, we must exercise that nobler willpower. Likewise virtue, godliness, kindness, and the like. This means letting the spirit override the physical urges and mental pretences and conceits. It flows naturally from real faith. Real faith in the teachings and the moral and truthful standard of these teachings brought into the world by Jesus Christ tends to lead a person to seek to overcome physical and mental natural impulses which bring traps and death, and this overcoming requires exercise of the nobler will and powers which is spiritual, with the seeking of God’s help, which is also spiritual. So when Paul says to live by the spirit, he does not explain it, but we find it implicit in the other teachings of the Christ and his apostles.
I asked an AI tool to expand this into an essay, and was given the following.
Modern readers often struggle to understand what Jesus and His apostles meant when they spoke of “the spirit.” The word has become vague and mystical in contemporary usage, yet in the world of the first century it carried a clear and practical meaning rooted in ancient moral psychology. When this historical framework is recovered, the New Testament’s teaching on spiritual life becomes not only intelligible, but profoundly practical.
In the intellectual climate surrounding early Christianity, many thinkers — including Plato — understood the human being as possessing three interrelated dimensions: the body, the mind, and the spirit. The body was the seat of appetites and impulses. The mind was the center of reasoning, imagination, emotion, and personal identity. The spirit, however, was regarded as the nobler faculty of the person — the seat of moral courage, conscience, and governing will. Plato described this element as that within us which sides with reason against appetite and is capable of choosing what is good even when such choices require sacrifice.
This framework illuminates the teachings of the apostles. When Peter urges believers to “add to your faith virtue, knowledge, self-control, perseverance, godliness, brotherly kindness, and love,” he is not offering a random list of moral traits. He is describing the gradual formation of the spiritual nature — the strengthening of the higher self that governs the whole person. Each of these qualities requires the exercise of the nobler will. Self-control demands resistance to bodily impulse. Perseverance requires endurance against emotional fatigue. Knowledge, virtue, and godliness require the rejection of mental distortion, pride, and self-deception. Kindness and love demand the overcoming of selfish instinct. These are not merely emotional developments; they are achievements of the spirit’s rule within the human being.
This same understanding lies behind Paul’s instruction to “live by the Spirit.” He offers little abstract explanation because his audience already shared this moral framework. To live by the Spirit meant allowing the highest faculty of the self — the morally awakened will — to govern both the body and the mind. The “flesh” that Paul warns against is not simply physicality but the ungoverned combination of bodily impulse and ego-driven reasoning. The “fruit of the Spirit,” by contrast, are the stable character traits that emerge when the spirit rules: self-control, patience, goodness, faithfulness, and love.
True faith therefore is not merely intellectual assent. It is the realignment of the ruling center of the person. When a person truly believes the teachings and moral authority of Jesus Christ, that belief awakens the spirit and compels the individual to resist destructive impulses and false mental patterns. This struggle is not won through human strength alone. The apostles speak of God’s Spirit assisting the believer because divine truth strengthens human will, enabling the spirit to govern rightly.
When the spirit rules, the human person moves toward life. When the flesh and ego rule, the person moves toward confusion and destruction. The New Testament’s call to spiritual life is therefore a call to moral order within the self — a restoration of the hierarchy in which the nobler will governs desire, thought, and action under the guidance of God.
To “walk in the Spirit,” then, is not to escape the world, but to live in it under the steady leadership of the highest and best within us, strengthened by faith and aligned with the truth that Christ brought into the world.
