there is no such word.
"Stillness" rhymes with darkness and means calm, quiet, or still.
Cherish rhymes with perish.
shall not perish means...won't die.
Some words that rhyme with "parish" are cherish, perish, and embarrassed.
Love or perish means to essentially, love or suffer.
Die, disappear
"Shall not perish" typically refers to something that will not cease to exist or be destroyed, indicating longevity or permanence.
They are approximate rhymes, but not exact rhymes. That would have to be "harkingness" and "darkingness" or "harkness" and "darkness." Most of those words, other than "darkness", aren't even real words. Look them up.
The word "perish" usually means to die, or pass away. It can also be used in the context of food, where the word "perishable" means that a food item can expire.
In the darkness I hear the chant?
darkness, heartless, handless..... u see where im getting at?
glee rhymes with sea and means rejoicing