2017-04-18 : Each Trial has an ability to return to your hand when a Cartouche enters the battlefield under your control. The Trial is returned to its owner’s hand only if it’s on the battlefield as the ability resolves.

2017-04-18 : If an effect allows you to exert a creature as it attacks, you may do so even if it has vigilance. It won’t be tapped.

2017-04-18 : Trial of Solidarity’s triggered ability affects only creatures you control at the time it resolves. It won’t affect creatures that come under your control later in the turn.