Sanctum of Eternity

Text:

: Add {C}.
, : Return target commander you own from the battlefield to your hand. Activate only during your turn.

Rulings:

• 8/23/2019 The “commander tax” increases based on how many times a commander was cast from the command zone. Casting a commander from your hand doesn’t require that additional cost, and it doesn’t increase what the cost will be the next time you cast that commander from the command zone.
• 8/23/2019 If your commander isn’t on the battlefield (or if you’re not playing the Commander variant), Sanctum of Eternity’s second ability does nothing.