Spell • Cost: 4
Ready one of your units.
Opposing exhausted units don't ready during their next ready step.
Purple • Present Magic
Readying one of your units CAN allow it to attack twice in a turn. (Attack with a unit, which will exhaust it. Play Ready or Not on that unit to ready it, then you can attack with it again.) — Sirlin, 03/02/16
If a unit has the readiness keyword, using Ready or Not on it won't let you attack twice in a turn with it because readiness specifically says you can't do that. — Sirlin, 03/19/16