No one could help thinking of the text in Job xxxviii. 7, 'When the morning stars sang together,' in this connection, and Milton naturally refers to it in the previous verse.
Here follow the two Shakespeare extracts. The second one is full of beauty of every kind, but the Pythagoreanism is in the last six lines, with Shakespeare's own view about why we cannot hear the heavenly music.
As You Like It II, vii, 5.
Duke Senior [of Jaques].
If he, compact of jars, grow musical,
We shall have shortly discord in the spheres.
Lor. My friend Stephano, signify, I pray you,
Within the house, your mistress [Portia] is at hand;
And bring your music forth into the air.
[Exit Stephano.
(Lorenzo and Jessica alone.)
Lor. How sweet the moonlight sleeps upon this bank!
Here we will sit, and let the sounds of music
Creep in our ears: soft stillness and the night,
Become the touches of sweet harmony.
* * * * *
L. 60.
There's not the smallest orb, which thou behold'st,
But in his motion like an angel sings,
Still quiring to the young-ey'd cherubims;
Such harmony is in immortal souls;
But, whilst this muddy vesture of decay
Doth grossly close it in, we cannot hear it.