Although Highway to Heaven was pretty, well, blah from an action viewpoint, the episode "Plane Death" featured Jonathan confronting men who'd killed Mark's friend for money; when they not only showed no remorse but also decided to kill him and Mark too, he went from mild-mannered helpful angel to Terminator, shrugging off punches, chair shots, and shotgun blasts with an emotionless face and throwing a few of the men across the room with one arm. When one panicked and confessed to the crime, he found Jonathan had vanished mid-confession... just in time for the ringleader's father, and the cops, to show up. Check it out.
Another time, a junkie tries to shoot Jonathan in a shop, who merely catches the bullet, gently tells him "that's a no-no," and brings down a pile of fruit, so that the man slips and falls. When being hauled away from the police, the junkie suffers a total BSOD.
In general, Jonathan showing how The Power of Love can literally work miracles (with a bit of help from Above, of course).