Watchman Nee discusses the concept of a 'soulish Christian,' emphasizing that while the sinful nature has been crucified, the soul remains influenced by Adam's fall. He explains that the soul, which encompasses the mind, emotions, and will, can still operate under its own power, leading believers to attempt to fulfill God's requirements through their natural strength rather than the Spirit. This results in a mixture of divine and human efforts, causing spiritual immaturity. Nee warns that relying on the soul-life to express God's nature can lead to a false sense of spiritual maturity, as believers may mistakenly believe they are living righteously while still being soulish. Ultimately, he calls for a deeper reliance on the Spirit to truly embody the life of Christ.