Maybe borrow/steal from Ars Magica a bit.
Divine Powers are White magic: Adjuration (control, banish the supernatural), Blessing (protective and inspirational aspects), Cursing ( smite those who oppose the Divine Will), Intervention ( sometimes God needs to step in a bit more directly), Transcendence (overcome the limitations of the material), Understanding (moments where the Divine Plan is clear), and Wonders (conjure holy items, creatures, and the elements).
Infernal powers are black magic: Consumption ( draw on life of others for your own use), Diablerie ( dealing with things from outside God's Creation), Effusion ( unnatural dominance of the natural world, without the ability to create), Malediction (direct damage to either fate (misfortune) or the world (withering and blasting curses)), Phantasm (Illusions and hallucinations), Psychomachia (control of thoughts and emotions).
Any other effects would be Grey, neither gifted from Heaven nor sold by Hell. Dealing with spirits, fae, elementals, ghosts, magical beasts, alchemy, wisdom gleaned from the stars and the potency of herbs. Okay, sometimes sold by Hell and maybe guided to by Heaven, but depending on neither. Just things you can learn if you pay attention or have the right teacher.
Regardless, I'd leave motivation out of the equation for what magic is what.
Calling down divine fire to lay waste to a horde of undead, but catching some humans in the blast isn't Black magic even though you have killed innocents. It is manslaughter, reckless endangerment, inappropriate use of Divine Resources, etc.. It is certainly going to get a very stern angel coming down to Have Words With Thee and possibly getting your Theurgy License revoked, but it is the act that is evil, not the magic.
Using a Phantasm or Psychomachia to trick or force a crime lord into confessing in court or make a serial killer walk off a ledge to a Disney Villain Death might do a lot of good, but you are still damned because the tools you are using are breaking Heaven's laws just by picking them up. To avoid cries of "foul!" and "I didn't know!" there is probably a section of an angelic choir dedicated to making sure that somebody about to learn Black magic is told at least once that it is a horrible plan.
Telling a salamander to go into an orphanage and burn everything that it can perceive is certainly murderous, but more like assault with an arcane weapon and less like possession of contraband. At least on a cosmic level. Individual countries might have anti wizarding laws on the books, but nobody is going to hell just for calling up a sylph. Using it to crash a ship onto a reef is probably not going to look good in your record, though.