And this song with az (then) ascends in the mouth. [Var. here ascends in the mouth, the ‘song of EL’] But ‘song’ (shir) is surely ‘the wisdom of Solomon’. At that time: (1 King. 5:10) And the wisdom of Solomon was greater... [For at that time: (Is. 11:9)... and the earth shall be full of knowledge of Ha-Shem etc.]
And who raises Her to Her place? It is Moses. And the mystery of the matter: ‘Then’ (az) shall Moses sing... (Ex. 15:1) With what does he raise Her? With the cantillation note ֠ te-lisha. This ‘crownlet’ of the te-lisha is the Yod י of YaShYR (he-will-sing).