The problem with the Greek words in the NT for soul and spirit, is that the context of their usage at times overlaps, revealing the translators often weren't sure how the difference between pneuma and psuche was really meant. Yet Hebrews 4:12 makes a distinction between the two revealing at the least, that spirit and soul are two different attributes of our being... distinct from our flesh body...
Heb 4:12
12 For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul (psuche) and spirit (pneuma), and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
(KJV)
Right there 3 different parts of our created being is made distinct from one another: 1) "soul", 2) "spirit", and 3) "marrow".
psuche means 'breath' (KJV as 'heart', 'life', 'mind', 'soul', 'us', 'you')
pneuma means 'a current of air' (KJV as 'ghost', 'life', 'spirit', 'mind')
Luke 23:42-43
42 And he said unto Jesus, "Lord, remember me when Thou comest into Thy kingdom."
43 And Jesus said unto him, "Verily I say unto thee, To day shalt thou be with Me in paradise."
(KJV)
Jesus told the malefactor he would be with Him in Paradise, not the next week, not at Christ's second coming, but THAT DAY.
But which part would be with Jesus in Paradise that day?
Apostle Paul already gave us in-depth descriptions of what kind of body the raising of the dead is. It is not a flesh body like we have today. It is a "spiritual body", what he also called "the image of the heavenly" (1 Cor.15). Is that of the "spirit" of Eccl.12? Yes. Does that also... contain the "soul" part? Yes. But is that about the flesh body we have today? NO.
In the heavenly, do the angels have an 'image'? Yes, and that's how Christ said we would appear in the resurrection per Matt.22:30, "as the angels of God in heaven." That aligns perfectly with what Paul declared that as we have borne the "image of the earthy", we shall also bear the "image of the heavenly" (1 Cor.15).
That also... aligns perfectly with our Lord's story of Lazarus and the rich man in Luke 16, where they both died, their flesh bodies buried, with the soul and spirit of Lazarus carried by the angels to one side in Paradise, and the spirit and soul of the rich man finding himself on the other side in hell (Greek haides).
The "spiritual body" is the outward image appearence in the heavenly dimension. But the 'soul' is the Id, or center of one's person or being. The flesh body is only a shell for the spiritual body and soul.
The angels have a spirit body image and a soul, but not a flesh body. The reason why Christ said in the resurrection we are "as the angels of God in heaven" is because when our flesh body is dead, the part of us that remains and continues, is our spiritual body image with soul (individual personality).
In 1 Cor.15:52 Paul made a distinction in the Greek with 4 different words, pointing to 2 different states of existence after death of our flesh bodies. One state is with the heavenly image spiritual body with a still liable to die mortal soul, and the other state is with a heavenly image spiritual body with a soul that is made immortal in Christ Jesus.
In 1 Peter 3, with Christ going to the "spirits in prison" and preaching The Gospel to them, they were NOT in flesh bodies, and those "spirits" were NOT just some animate force that went back to God that had no individual personality (i.e., soul).
So in Eccl.12, the distinction between the flesh body and spirit also includes one's soul (individual personality) along with that spirit that goes back to God Who gave it. God gave it because He created our 'spirit' part, and it is NOT just some animate force only, like what animates a grasshopper!
That this is not just a fanciful theory, even Kerulian photography has shown. Those type photos look like slide negatives. Plants with all its branches intact were photographed, and then a branch torn off with another photo taken. An aura type image of the torn off branch still existed in the 2nd photo, even though the plant branch was missing. This is why amputees have often complained about pain or itching of a limb long after the limb had been amputated. It's because the "spiritual body" part of the limb is still there intact, even though the flesh limb isn't.