Historical Rules · 14 June 2019
Rule 720.5
Official source text from the 14 June 2019 Rules release
No player can be forced to perform an action that would end a loop other than actions called for by objects involved in the loop. Example: A player controls Seal of Cleansing, an enchantment that reads, “Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.” A mandatory loop that involves an artifact begins. The player is not forced to sacrifice Seal of Cleansing to destroy the artifact and end the loop.