Crumble the bread quite small.
Melt the butter in a saucepan and add the onions and celery; cook until the onions are soft and beginning to show color.
Stir in the bread crumbs, add the parsley and thyme, salt and pepper.
Drain the oysters, reserving the liquor, and heat the liquor to the boiling point.
If the oysters are large, cut them in half, if small, use whole.
Add them to the liquor and cook until the edges start to curl.
Drain promptly and stir the oysters into the bread mixture.