This quote is an example. In this passage, Satan is discoursing with himself on his fall from grace. I note that the subjection of gratitude, to God who has graciously given all things to us who merit none, is also our duty--and that the temptation to resent that duty as a burden is also a human one. I like how the quote ends, acknowledging that what we may be tempted to call a burden is really nothing like--and belying Milton's unusual depiction of an eloquent and, perhaps, pitiable devil with Satan's orthodox rejection of his own delusion.
. . . lifted up so high
I'sdained subjection, and thought one step higher
Would set me highest, and in a moment quit
The debt immense of endless gratitude,
So burdensome still paying, still to owe;
Forgetful what from him I still received,
And understood not that a grateful mind
By owing owes not, but still pays, at once
Indebted and discharged; what burden then?
Book IV, Lines 49-57