Charles Ellicott Commentary Isaiah 56:11

"Yea, the dogs are greedy, they can never have enough; and these are shepherds that cannot understand: they have all turned to their own way, each one to his gain, from every quarter." — Isaiah 56:11 (ASV)

Shepherds that cannot understand ... —Better, and such are shepherds; they cannot understand. There is no confusion or change of metaphors. What is implied is that the prophets who are not fit to be watch-dogs of the flock, assume the office of its shepherds.

From his quarter — i.e., in modern phrase, from his own sphere of influence.