Both Ecclesiastes and Matthew are the books of the son of David. Ecclesiastesspeaks of the kingdom of the earth and concludes that it is all vanity. Matthew talks about the kingdom of heaven.  The Hebrew preacher is one who spoke publicly to gatherings. After Matthew takes care of some prophetic riddles he will portray Jesus as the preacher with the sermon on the mount.  In addition to these interesting observations, the two books play into the first-son, second-son theme. This is where the second some obtains the inheritance or promise where the first son loses it. The second book of the son of David show Jesus as the king, the second son of David (who has a book). The word generation in Hebrew is toledoth. It is more properly interpreted as "the record belong to or written by"