"All purity, all trial, all observance."
As 'observance' is the word in the riming line, Collier's folio and Malone read obedience; Heath perseverance; Harness and Singer, whom I find I have followed, endurance.
"Why do you speak too?"
I quite agree with those who read, with Rowe, Who and to.
Sc. 3.
"Yet the note was very untuneable."
Theobald read untimeable, as the reply is "we kept time;" but, as time and tune were synonymous, there seems to be no need of change.