Dryad Arbor can never be cast from your hand (or anywhere), so it can never enter the battlefield with Containment Priest around!
Containment Priest vs. Show and Tell
Containment Priest can only affect things that enter while it's already in play. So anything that enters at the same time, like with Show and Tell, will be able to enter normally.
Comeuppance + Comeuppance = a drawn game.
Comeuppance can do cool and weird things in combat (and two players with Comeuppance can result in a draw!). Learn about it here!
Assault Suit – What “can’t be sacrificed” means.
There have been a few cards that prevent sacrifices from opponent's effects, but "can't be sacrificed" is a new ability, so we explain exactly what it means for Assault Suit!
How Arcane Lighthouse works.
Similar to the Archetype cycle, Arcane Lighthouse removes hexproof/shroud and makes sure it can't be regained this turn!
The “lieutenant” abilities know about commanders that are face-down or copying something.
A commander by any other name (or status) is still a commander, as far as the lieutenant abilities are concerned.
You can’t cast Aether Gale without choosing 6 nonland permanents.
If a spell requires 6 targets, you can't cast it without that many targets to choose!
Casting a god doesn’t trigger prowess (but a bestowed card will).
A god spell will always be a creature, and thus can't trigger prowess. But a bestow card cast as an aura is indeed a noncreature spell, and can trigger prowess.
Clan combos – Jeskai and Temur: You can use Prowess to “turn on” a spell’s Ferocious effect.
Prowess triggers when you cast a noncreature spell, while the spell you just cast only checks whether Ferocious is true as it resolves. Since the trigger goes on top of the spell and resolves first, this generally works out well for you!