If the target creature becomes an illegal target for Take Heart, the spell doesn’t resolve. You don’t gain life.
05-10-2018
wotc
You can cast Take Heart even if you control no attacking creatures, perhaps because it’s not even your turn. The target creature gets +2/+2 even though you don’t gain life.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.