It Seems Solomon Did Not have the Full Revelation of Salvation, because he concluded, "All is Vanity"?
Solomon explains that the spirit of man is different than that of the beast! And he knew the flesh of both, man and beast returns to dust! But it seems Solomon did not have full revelation of the "salvation story"; probably, because the full mystery of salvation in Christ Jesus was not revealed until the ministry of Jesus, by Jesus!
Jesus filled in; fulfilled, and revealed final details from God of what we should expect; then He ascended into heaven again!
This is revealed for us today in the sacrificial salvation "Message of the Cross of Christ Jesus"; which no one had been given total revelation of until Messiah Jesus gave it during His three and one-half (3 1/2) year ministry (Refer to Matthew Chapter 12:38 through 12:42:
Then certain of the scribes and of the Pharisees answered, saying, Master, we would see a sign from thee (to prove who you say you are?).
But he (Jesus) answered and said unto them, An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas (who was in the whale's belly three (3) days and three (3) nights):
For as Jonas was three (3) days and three (3) nights in the whale's belly; so shall the Son of man be three (3) days and three (3) nights in the heart of the earth.
The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonas; and, behold, a greater than Jonas is here.
The queen of the south shall rise up in the judgment with this generation, and shall condemn it: for she came from the uttermost parts of the earth to hear the wisdom of Solomon; and, behold, a greater than Solomon is here.
Matthew 12:38 through 12:42