The answer
The three books of King Solomon correspond to the three steps in one’s spiritual life: Proverbs is the book of “wisdom”, Ecclesiastes is the book of “vanity”, and Song of Songs is the book of “love”. By “wisdom” we mean the spiritual wisdom from God, not the earthly philosophical wisdom. After gaining spiritual wisdom and being enlightened by God’s divine light, you will come to the realisation that this world is “vanity”, because all will vanish. And once you will come to the realisation about the world, you will look towards the Kingdom of Heaven and the King of Heaven, our beloved Lord Jesus Christ. You will devote yourself and your time to Him, and thereby you will be united to Him through love.
H.G. Bishop Moussa