Rebbe Nachman speaks at length (Likutei Moharan Tinyana 8) about a special song that will be awakened in the future. This song will be used by Moshiach to guide people out of the depths of their sins. This is the song that the Torah speaks about when it says 'az yashir Moshe' - then Moshe and the children of Israel will sing. It is a song that comes after a break in tension. It is the cosmic tension of the end of days, similar to when the Jewish people seemed at the edge of destruction as they stood at the Yam Suf, with the sea on one side, and the Egyptians coming to destroy them on the other. This tension broke with the miracle of the splitting of the sea, and climaxed with their salvation and the song at the sea, which we will sing again in the future. Again, we will face near extinction, and Hashem will again perform the ultimate miracles to save us. Only this time, it will be once and for all.
There is a midrash that talks about the seven stringed instrument that was played in the past, that will be replaced by an eight stringed instrument when Moshiach comes. It will be replaced, again, by a ten stringed instrument in the world to come.
You may have heard of the mysterious 'eighth note,' which seems to be implied by this midrash. You may also know that the current scale only contains seven notes - the eighth note is the same as the first, only higher (hence it is called an octave). But this 'eighth note' of the future is something different.
I always thought that it was some type of combination of all the notes, some interdependent transcendent note... or something. Most recently, I realized that it may be so, but there might be a different aspect to this eighth note. And you might already have started to hear this eighth note, if you've been listening out...
The concept of seven always has to do with the physical realm, which was created in seven days. This also corresponds to the seven lower sefiros (out of ten). We also call this teva - nature. Then there is the eighth aspect, which is transcendent, and corresponds to the sefirah above these seven, which is Binah. Binah translates as intuition. This is the aspect which is l'malah min hateva - above nature. This is very much connected to how our intuitive faculty functions - it fills in the gaps. It also corresponds to the aspect of Neshama - soul.
In essence, we could say that there is a seven-stringed instrument which is for this world, which is the physical, natural aspect of the music. Then there is an eighth note, which has the neshama - soul in the music. This is a song that isn't about love between a man and a woman. It's also not a song that has lyrics slap-dashed together, without being such a good fit for the tune. It is a song about our soul's thirst for God. Or it is a song that gives us hope that Hashem will take care of us, despite all of our challenges. Or it is a song that inspires us to love each other. Or it is a song that inspires us to be better people.
There are many songs out there to listen to. How many notes are in your songs?