Chant

Az yashir — then he will sing. The verb is in the imperfect, which has occupied commentators for centuries, and the plain reading is enough for this chapter: at the sea, the response to what had happened was not a statement.

What song does that speech cannot

Speech is optimised for finishing. A sentence delivers its content and ends, and a good sentence ends efficiently. This is what makes speech the faculty of malchus: it transmits, and transmission wants to complete.

Song does not finish in the same way. It repeats, it returns, it holds a syllable past the point where the information has been delivered. Anyone who has sung a niggun without words has done something that speech cannot do: sustained a relation to something without asserting anything about it.

Dissonance

A musical tradition that only used consonance would have nothing to say about exile. What makes resolution meaningful in music is that it resolves something — the tension is not a defect in the piece, it is the mechanism by which the piece means anything.

The Chassidic niggun is unusual among religious musics in how much unresolved material it carries. Many of them are in minor modes and stay there for long stretches. The joy in them is not the absence of the minor; it is what the minor turns into without being denied.

The song of the future

The Levitical service in the Mikdash was musical, and the sources describing the future service keep the music — including the eighth string of the previous chapter.

And the verse from Tehillim pairs laughter with rinah, song. Not with explanation. The resolution the tradition anticipates is described in the register of music rather than of argument, which is a claim about what kind of resolution it is.