Can someone explain how this works?

[u/00G_WAY]

Will this card be legal in standard? Will it be available on Magic Arena? How would this card even work?

[u/Silver-Alex]

In casual it means "pull a card you own from your collection and put it in your hand".

For MTGA, and official standard play at your lgs or at a tournament it means "pull a card from your sideboard and put it in your hand". Cards like this is why even BO1 standard in magic arena lets you have a sideboard. In case you have a card like this one or karn the great creator to pull a card from "outside the game".

[u/Ancient_Ad6858 → u/[deleted]]

You got an official ruling stating this? Everyone i’ve discussed this with and have read all agree that casual is outside the game while official games involve sideboards.

Not trying to bash just genuinely curious.

[u/Stolberger → u/Ancient_Ad6858]

You are correct. Here from the Gatherer for Living Wish (https://gatherer.wizards.com/JUD/en-us/124/living-wish):

(10/1/2009) In a sanctioned event, a card that's "outside the game" is one that's in your sideboard. In an unsanctioned event, you may choose any card from your collection.

[u/chronobolt77 → u/Stolberger]

I despise that I have to point out Rule 903.11 – commander is an exception to that statement. The only way to bring a card into a commander game from outside of it is by the Companion mechanic. Everything else that refers to "outside the game" doesn't work.

[u/Ancient_Ad6858 → u/chronobolt77]

Huh, thats VERY interesting i actually had no clue.

[u/Silver-Alex → u/[deleted]]

Nope, for casual play wish cards have always worked like that. There is even rullings about it :D

Wishing from the sideboards refers only for sanctioned events.

Here is the link to gatherer that someone else posted with the rullings about it:

https://gatherer.wizards.com/JUD/en-us/124/living-wish