Proverbs 20:27 says, "The spirit of man is the lamp of Jehovah" (ASV). Generally speaking, the word in Hebrew for spirit is ruach, but the Hebrew word for spirit here is neshamah. Neshamah is the same word used in Genesis 2:7 for breath. In Proverbs 20:27 it is translated spirit. By this we can see that the breath of life breathed into man by God at man's creation was the spirit of man. The spirit of man is something within us that is very close to God's life and God's Spirit. This indicates that the spirit of man was created for the purpose of receiving and containing the life of God and the Spirit of God. Eventually, 1 Corinthians 6:17 says, "He who is joined to the Lord is one spirit." Our spirit can become one spirit with the Lord because it was created with the breath of life, which is very close to God's life and God's Spirit.
Zechariah 12:1 says that the Lord stretched forth the heavens, laid the foundation of the earth, and formed the spirit of man within him. No one can deny that these three items—the heavens, the earth, and the spirit of man—are crucial in God's creation to fulfill His purpose. The heavens were created for the earth, the earth was created for man, and man was created for God.
Zechariah does not refer to "man," but to "the spirit of man." This is because the spirit of man is the very organ that can take in God to enjoy God's life and God's Spirit and be one with God's Spirit. This is why man's spirit has become so crucial and important, even to the extent that it is ranked with the heavens and the earth. The philosophy of man does not rank anything of man with the heavens and the earth. But Zechariah ranks man's spirit with them. This shows how important the human spirit is.
We have to point this out to the saints. We need to give a training lesson in which we point out that our human spirit was created with a material that is very close to God's life and Spirit. We also need to point out that our spirit is so important that it is ranked with the heavens and the earth.
It is not easy to pick up a verse or verses which directly show that the conscience is a part of the spirit. We have to compare Romans 9:1 with 8:16. Romans 9:1 says that our conscience bears witness with us in the Holy Spirit, whereas 8:16 says that the Holy Spirit witnesses with our spirit. These two verses strongly prove that our conscience is a part of our spirit. In 1 Corinthians 5:3 Paul judged a sinful one in his spirit. To judge is to condemn sin, and that is mostly the function of the conscience. Psalm 51:10 speaks of "a right spirit within me" (KJV). This is a spirit which is right. Knowing right from wrong is related to the conscience, so this verse shows that the conscience is in the spirit. Other verses we can use to show the function of the conscience as a part of the spirit are Psalm 34:18 and Deuteronomy 2:30. For verses related to the parts of the human spirit, we need to read The Economy of God, pages 56-59.