Historical Rules · 13 October 2023
Rule 302.6
Official source text from the 13 October 2023 Rules release
A creature’s activated ability with the tap symbol or the untap symbol in its activation cost can’t be activated unless the creature has been under its controller’s control continuously since their most recent turn began. A creature can’t attack unless it has been under its controller’s control continuously since their most recent turn began. This rule is informally called the “summoning sickness” rule.