It is so important to understand the distinction between the human spirit and the soul. It is not the soul that is united with God, but the spirit—for the spirit was created for union with God; indeed, it cannot live out of union with God. As a result of regeneration, the spirit of the born-again believer is able to unite with God.
Let us review three simple descriptions of the orientations of spirit, soul, and body. The spirit is God-conscious. The soul is self-conscious. The body is world-conscious.
Through our spirits, we are conscious of God. In our souls, we are conscious of ourselves. And through our bodies and their senses, we relate to the world around us.
When man’s spirit is reunited with God, the rekindled spirit becomes a lamp. Filled with the Holy Spirit, it illuminates the inward nature of man which was dark and alienated from God up to that time. We need to remember that when the Bible was written, the fuel for every lamp was olive oil, and olive oil is always a type, or symbol, of the Holy Spirit.
The spirit of man is the lamp of the Lord, searching all the innermost parts of his being. (Proverbs 20:27 nasb)
When the spirit of man is brought back into union with God and the Holy Spirit comes in and fills up that lamp, then the lamp inside man—his spirit—is illuminated, shedding light on his entire inner being. He is no longer in darkness.