There are a few scriptures that hint at this concept but none in the old testament. In fact the old testament is clear that dust you are and to dust you shall return. King Solomon said that the dead know nothing and every single person who was described as dying in the old testament was said to "sleep with his fathers".
The body goes back to dust, the soul departs the body at death:
Ecc 12:7 then man's dust will go back to the earth, returning to what it was,
and the spirit will return to the God who gave it.
The Old Testament actually backs up 2 Corinthians 5 which states our body is a house, a tent, that we depart from at death.
In 1 Kings, Elijah prayed three times for a dead boys SOUL to come back into his body. When his SOUL returned to his body again, the dead child was alive again. His soul wasn’t asleep with his dead body, it had LEFT and had to return.
1Ki 17:20 And he cried unto the LORD, and said, O LORD my God, hast thou also brought evil upon the widow with whom I sojourn, by slaying her son?
1Ki 17:21 And he stretched himself upon the child three times, and cried unto the LORD, and said, O LORD my God, I pray thee, let this child's SOUL come INTO HIM AGAIN.
1Ki 17:22 And the LORD heard the voice of Elijah; and the SOUL of the child CAME INTO HIM AGAIN and he revived.
1Ki 17:23 And Elijah took the child, and brought him down out of the chamber into the house, and delivered him unto his mother: and Elijah said, See, thy son LIVETH.
Not to mention Moses died, but HE departed from his home, the body (2 Corinthians 5), and he appeared to Jesus on the mount of transfiguration.
Mark 9:4.
When Rachel was dying, her soul was departing.
Gen 35:18 And as HER SOUL WAS DEPARTING (for she was dying), she called his name Ben-oni; but his father called him Benjamin.
Gen 35:19 So Rachel died, and she was buried on the way to Ephrath (that is, Bethlehem),
Where was her soul going when it departed from her body?
Back to God:
Ecclesiastes 12:7 then man's dust will go back to the earth, returning to what it was,
and the spirit will return to the God who gave it.