begone, be gone

Begone or begone ( one word ) is a command to go away or leave--
"Begone, Satan: for it is written..."
"Begone, you have no power here!"

Be gone or be gone ( two words ) means to ( be ) departed, used up, or past ( gone )--
I hope these customers will be gone soon.
How could all of the pizza be gone?
When will your crutches be gone?

Now that you know that, you can say--
"It seems these stray cats will never be gone; I just yell "begone!" at them when I see them."

Note--"woebegone" means showing sorrow or woe; sad-looking, literally or figuratively--
What a woebegone place. It makes me feel sad just to look at it.