The Spirit Of Man Bible scriptures located in Ecclesiastes 3:18-22 explains directly from God's Word the Spirit Of Man topic.
I said in mine heart concerning the estate of the sons of men, that God might manifest them, and that they might see that they themselves are beasts.
For that which befalleth the sons of men befalleth beasts; even one thing befalleth them: as the one dieth, so dieth the other; yea, they have all one breath; so that a man hath no preeminence above a beast: for all is vanity.
All go unto one place; all are of the dust, and all turn to dust again.
Who knoweth the spirit of man that goeth upward, and the spirit of the beast that goeth downward to the earth?
Wherefore I perceive that there is nothing better, than that a man should rejoice in his own works; for that is his portion: for who shall bring him to see what shall be after him?