What you're preaching is Old Testament doctrine about death and the grave, i.e., the JEWS' TRADITIONS of Judaism. I say Jew's traditions because they often don't even follow all the Old Testament writings either, like this...
Eccl 12:5-7
5 Also when they shall be afraid of that which is high, and fears shall be in the way, and the almond tree shall flourish, and the grasshopper shall be a burden, and desire shall fail: because man goeth to his long home, and the mourners go about the streets:
6 Or ever the silver cord be loosed, or the golden bowl be broken, or the pitcher be broken at the fountain, or the wheel broken at the cistern.
7 Then shall the dust return to the earth as it was: and the spirit shall return unto God who gave it.
KJV
In John 3 Lord Jesus contrasted the difference between flesh and spirit, and Nicodemus, a Jewish Pharisee didn't understand, obviously because of the traditions of the Jews. Jesus said that which is born of the flesh is flesh, and that which is born of the Spirit is spirit.
Apostle Paul further explained this difference in 2 Corinthians 5 when he said that if our flesh earthly house were dissolved, we have a BUILDING OF GOD, a house not made with hands, eternal in the heavens (2 Corinthians 5:1).
In Matthew 10:28, Jesus said to not fear those who can kill our body (flesh), but not our soul, but fear Him Who can kill both body (spiritual body) and soul in geenna (rendered "hell" in KJV, but is pointing to the future "lake of fire").
When these New Testament Truths are weighed in conjunction with that Eccl.12:5-7 Scripture, it reveals our flesh body is NOT our true self, but is only a shell God created for our spirit with the soul. Thus spirit-soul are together and cannot be separated, but our spirit-soul can be separated from our flesh. The severing of that "silver cord" for example, allows the separation of our flesh to go back to the earthly elements where it came from. But our spirit (with soul) continues on to The Father Who gave it, which in Luke 16 Lord Jesus showed that means one's spirit taken to Paradise in the heavenly dimension, on one side of the great gulf or the other.
The Jew's tradition on that "spirit" of Eccl.12 is according to their old belief about the flesh. Because of how Genesis 2 is written about God creating Adam a living soul, they assume that means the soul cannot exist without flesh, which led them to interpret the "spirit" going back to God as just being a force that all living things have, much like that 'spirit' is similar to a drop of water going back into the Great Ocean (symbolic for God). That in reality is what the occultists believe. They believe our soul is just a small drop of water separated from The Great All of the Cosmic, or Great Soul, and when we die our drop of water blends back into The Great All. Problem with that untruth is that 'we' as individuals would cease to exist.
The New Testament teaches how God actually created us with both a spirit with soul into a flesh shell. The flesh is ordained to perish, but our spirit with soul is ordained to eternal Life by being "born again" through Faith on His Son Jesus Christ, but only for those who believe on The Father through His Son Jesus Christ. Even after flesh death, for those who don't believe on Jesus Christ, there still exists a second death for them, but not a death of flesh again, but to their spirit with soul in the future "lake of fire".