The Divine Word spell description says:
Regardless of its current hit points, a celestial, an elemental, a fey, or a fiend that fails its save is forced back to its plane of origin (if it isn't there already) and can't return to your current plane for 24 hours by any means short of a wish spell.
Is a celestial spirit summoned with the Find Greater Steed spell affected? I'm not sure if it has a plane of origin.