Psalm 146:4 states that when the
ruach leaves us, we go back to the ground, and our thoughts perish.
This does not say that just our thoughts in our body perish, and that we continue to have thoughts in a spirit form. It plainly says that our thoughts perish -- period. This agrees with the plain statement of Ecclesiastes 9:5.
nowhere does the Bible teach or imply that the
ruach of human beings is a spirit being or consciousness that can be separated from the body; for the Bible does not teach that we are hybrids, part human and part spirit beings.
"the ruach shall return to God who gave it," cannot mean a spirit being or some consciousness that lives on in conscious existence after the death of the body. Such a thought has to be added to the scripture.
according to Ecclesiastes 12:7, our bodies return to their native dust (Genesis 3:19), and our life force or energy reverts to its Giver, God, in the sense that He takes it from us and keeps it in His power for whatever final disposal of it He will be pleased to make at the Judgment Day.
In Ecclesiastes 12:7 can be seen
the reversal of the original creation process as described in Genesis 2:7.
http://reslight.addr.com/thespirit.html