When Oath of Teferi enters the battlefield, exile another target permanent you control. Return it to the battlefield under its owner's control at the beginning of the next end step.
You may activate the loyalty abilities of planeswalkers you control twice each turn rather than only once.
4/27/2018 If a token is exiled this way, it ceases to exist and won’t return to the battlefield.
4/27/2018 The exiled card will return to the battlefield at the beginning of the next end step even if Oath of Teferi is no longer on the battlefield at that time.
4/27/2018 If the exiled card is an Aura, that card’s owner chooses what it will enchant as it returns to the battlefield. An Aura put onto the battlefield this way doesn’t target anything (so it could be attached to an opponent’s permanent with hexproof, for example), but the Aura’s enchant ability restricts what it can be attached to. If the Aura can’t legally be attached to anything, it remains exiled.
4/27/2018 For Oath of Teferi’s second ability, you may activate the same ability of a planeswalker twice, or you may activate two different abilities of that planeswalker.
4/27/2018 If you somehow control more than one Oath of Teferi, you won’t be able to activate abilities of planeswalkers you control more than twice in one turn.