Angel of Condemnation

• WOTC Official Reminder Textofficial rules
  Vigilance — Attacking doesn't cause this creature to tap.

• WWizards of the Coast2017-04-18
  Official Ruling
  If you gain control of another player’s creature until end of turn and exert it, it will untap during that player’s untap step.
• WWizards of the Coast2017-04-18
  Official Ruling
  If an exerted creature is already untapped during your next untap step (most likely because it had vigilance or an effect untapped it), exert’s effect preventing it from untapping expires without having done anything.
• WWizards of the Coast2017-04-18
  Official Ruling
  You can’t exert a creature unless an effect allows you to do so. Similar effects that “tap and freeze” a creature (such as that of Decision Paralysis) don’t exert that creature.
• WWizards of the Coast2017-07-14
  Official Ruling
  If a creature token is exiled this way, it will cease to exist and won’t return to the battlefield.
• WWizards of the Coast2017-07-14
  Official Ruling
  If Angel of Condemnation leaves the battlefield before its first activated ability resolves, the target creature is still exiled. That card returns to the battlefield even if Angel of Condemnation has left the battlefield before the next end step.
• WWizards of the Coast2017-07-14
  Official Ruling
  The card exiled with Angel of Condemnation’s last ability returns to the battlefield immediately after Angel of Condemnation leaves the battlefield. Nothing happens between the two events, including state-based actions.
• WWizards of the Coast2017-07-14
  Official Ruling
  Tapping Angel of Condemnation to activate either of its abilities while it’s attacking doesn’t remove it from combat.
• WWizards of the Coast2017-07-14
  Official Ruling
  If Angel of Condemnation leaves the battlefield before its last ability resolves, the target creature won’t be exiled.
• WWizards of the Coast2017-07-14
  Official Ruling
  Some cards in the Hour of Devastation set let you exert a creature as a cost to activate one of its abilities. You can exert it to pay that cost even if you’ve already exerted it earlier in the turn. Exerting it multiple times will keep it tapped only during your next untap step.
• WWizards of the Coast2017-07-14
  Official Ruling
  Auras attached to the exiled creature will be put into their owners’ graveyards. Any Equipment will become unattached and remain on the battlefield. Any counters on the exiled permanent will cease to exist.

Rulings via Scryfall