Midrash sobre II Crónicas 1:12

Another matter, “the words of Kohelet, son of David” – three prophets, because their prophecies were matters of rebuke, their prophecy is attributed to them. These are: “The words of Kohelet”; “the words of Amos” (Amos 1:1); “the words of Jeremiah” (Jeremiah 1:1).⁴This stands in contrast to, for example, the beginning of the book of Joel, which states: “The word of the Lord that came to Joel son of Petuel.” God does not attach His name to negative matters.
Why was his name called Jeremiah? It is because in his days, Jerusalem became desolate [irmeia]. Amos, why was his name called Amos? Rabbi Pinḥas said: It is because his tongue was encumbered [amus]. The people of his generation said: The Holy One blessed be He overlooked all His creations and rested His Divine Presence only on this stutterer with a severed tongue? Kohelet, why was his name called Kohelet? It is because his words were stated in an assembly [hak’hel], as it says: “Then Solomon assembled” (I Kings 8:1). Rabbi Aḥa in the name of Rav Huna: One group would enter as another group was exiting, to hear Solomon’s wisdom. That is what the queen of Sheba said to him: “Happy are your people, happy are these servants of yours” (I Kings 10:8), and it is written: “There came from all the peoples to hear Solomon’s wisdom” (I Kings 5:14).
He was called by three names: Yedidya, Kohelet, Solomon. Rabbi Yehoshua says seven: Agur, Yakeh, Lemuel, Itiel.⁵In addition to Yedidya, Kohelet, and Solomon. Shmuel said: The most primary and authentic among them are Yedidya, Kohelet, Solomon. Rabbi Shmuel concedes regarding these [other] four, but they were epithets given to Solomon, and they were given to be expounded: Agur, as he was filled [agur] with matters of Torah. Yakeh, as he would expel [heki] his words, like this basin that at times is full and at times is emptied; so, Solomon, at times he studied Torah and at times he would forget it.⁶This was when his heart strayed from following God. Lemuel, as he spoke [nam] to God [El] in his heart and said: I can increase⁷Horses, wives, and money, see Deuteronomy 17:16–17. and not sin. Itiel, as he said: God is with me [iti El] and I am able.⁸To marry numerous women.
“Son of David” – king, son of a king, wise man, son of a wise man, a righteous man, son of a righteous man, a nobleman, son of a nobleman.
Rabbi Yudan in the name of Rabbi Alexandri: This ox, until its tendons are cut, it can be suspended by even one tendon. Once its tendons are cut, numerous ropes and numerous nails are needed to suspend it. So too, until Solomon sinned, he would depend on his own merit, but once he sinned, he was dependent on the merit of his fathers; that is what is written: “[However, I will not tear away the entire kingdom; I will give one tribe to your son] for the sake of David, My servant” (I Kings 11:13). Rabbi Shimon ben Yoḥai taught: Happy is one who was privileged to reign in a place of royalty. There it is written: “[Og, king of Bashan,] who dwelled in Ashtarot in Edre’i” (Deuteronomy 1:4), but here, “king in Jerusalem,” in a place of royalty.

Another explanation: "And you shall take for yourselves on the first day" - in spite of all of that wisdom that is written about Shlomo (II Chronicles 2:1), "wisdom and knowledge are granted to you;" (I Kings 5:10-11) "And the wisdom of Shlomo grew... And Shlomo was wiser than all men," these four species were perplexing to him, as it is stated (Proverbs 30:18), "Three are there that are wondrous beyond me" - these three are the Pesach sacrifice, matsa and marror (bitter herbs) - "and four which I did not know" - these four are the four species of the lulav, that he sought to understand: "The fruit of a beautiful tree" - who will tell me that it is a citron (etrog)? All of the trees make beautiful fruit (and are hence called beautiful trees). "The branches of a date palm" - the Torah said, "take two palm branches (as 'branches' is in the plural) to praise with" and he only takes a [singular] lulav, which is the heart of the date palm. "And a branch of a braided tree (a myrtle)" - who will tell me that it is a myrtle? Behold, in another place it says (Nechemiah 8:15), "Go out to the mountain and bring olive branches, etc" (the verse continues to list several species and mentions myrtles alongside branches of a braided tree, seemingly indicating that they are two different species). "And brook willows" - all trees grow in the water! [Hence,] "and four which I did not know." He came back and mentioned them a different time, as it is stated (Proverbs 30:29), "There are three that are good, etc." - these are the four species, that each and every one in Israel goes and runs and takes from them for himself, to praise the Holy One, blessed be He. And [the four species] appear small in the eyes of man but they are great in front of the Holy One, blessed be He. And who explained to Israel that they were these four species, which are the citron, the palm branch, the myrtle, the willow? The Sages; as it is stated (Ibid., verse 24), "they are very wise sages."