If an effect refers to a “[subtype] spell,” it refers only to a spell that has that subtype. For example, Knights' Charge is a card with “Knight” in its name and benefits Knights, but it isn't a Knight card.
04-10-2019
wotc
Worthy Knight's triggered ability won't trigger when you cast it because it's not on the battlefield yet.
04-10-2019
wotc
Worthy Knight's ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered.
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.