Excerpts from The Messenger of the Cross by Watchman Nee:
Page 26: “Let us read another Scripture passage to help us understand what is the difference between depending on natural life and depending on supernatural life. ‘Verily, verily, I say unto you, Except a grain of wheat fall into the earth and die, it abideth by itself alone; but if it die, it beareth much fruit. He that loveth his life loseth it; and he that hateth his life in this world shall keep it unto life eternal’ (John 12.24, 25).”
Page 28: “But what does this phrase ‘fall into the earth and die’ really mean? By reading the succeeding words which the Lord utters here, we may readily understand: ‘He that loveth his life loseth it; and he that hateth his life in this world shall keep it unto life eternal’ (12.25). In the Greek original, two different words are used for the several times ‘life’ is mentioned here. One Greek word psuche has reference to the soul life or natural life; the other word zoe signifies the spirit life or supernatural life. Hence what the Lord is actually saying here is: ‘He that loveth his soul life loseth the spirit life; and he that hateth his soul life in this world shall keep the spirit life unto eternity.’ To put it simply, we should deliver the soul life to death, just as the grain of wheat falls into the earth and dies; and then by our spirit life many grains will come forth and be kept to eternity. How we long to bear much fruit, yet we do not know how to let the soul life die and the spirit life live.
“Soul life is our natural life. It is the soul life which enables our flesh to live. It is therefore the life factor of the natural man. A person’s natural endowment belongs to the soul—such elements as our will, strength, emotions, thought, and so forth. These things which all natural lives share in common are accessories of the soul life. Our cleverness, reasoning, eloquence, affection, and ability belong to the soul life. The spirit life, though, is the life of God. It is not an evolvement from any part of the soul life but is a life especially given to us by the Holy Spirit when we believe in the finished work of the cross of the Lord Jesus and are saved. God is then in us to quicken this spirit life so that it may grow and thus become the power of all our good deeds and works. It is the will of God for Him to put our soul life in the place of death (note, however, that this is different from the death prescribed in 2 Corinthians 4).”