The Greatest Song

The Mishna in Yadiem at the end of chapter 3 says that all of Ketuvim is קדוש but Shir Hashirim is קודש קדשים.  What makes Shir Hashirim קודש קדשים?  Many explain (Kehati brings it from Rav Yisroel Salanter,) that normally the Torah can be elucidated via the four levels of פרדס; פשט רמז דרוש וסוד.  However, Shir Hashirim can only be understood on the levels of remez and sod, there is no simple interpretation.  Why is that Shir Hashirim is written in such a cryptic manner?

In ישתבח we say הבוחר בשירי זמרה translated as who chooses melodious songs.  Rav Simcha Bunim translated the word בשירי like שיירים - what is left over (cited by Artscroll in the commentary to the siddur, brought down in Sfas Emes.)  In the leftovers of the praise, the feelings that are too great to be expressed through words that is the most precious to Hashem.  The greatest praise is that which can’t be expressed in words. 

The great love that exists between Hashem and Klal Yisroel is too great to be expressed in words.  That’s why there can be no simple peshat to Shir Hashirim.  It is impossible to contain the love expressed in the vessels of words and it can only be eluded too.

The Shira is written as a half brick on top of a whole brick (Megillah 16b.)  There are large gaps between the words.  Why is shirah written in this odd manner?  Rav Aharon Solovetchik (cited in introduction to Gan Shosanim volume 1,) explained that the empty spaces are filled with the unwritten shirah, the shirah of the heart.  It is the unwritten song that is indeed the greatest song.