He was attacking with this card, and I blocked it with two creatures because of the double strike. My opponent USED THE ACTIVE ABILITY which clearly says TAP Seasoned Hallowblade. His attack
How Does Blocking Work in "Magic: The Gathering?" - HobbyLark
How Does Blocking Work in "Magic: The Gathering?" - HobbyLark
Blocking in Magic: All Your Rules Questions Answered - Draftsim