Fervor
Enchantment
Creatures you control have haste. (They can attack and 
as soon as they come under your control.)
"We won't sit like lazy gob-slugs waiting for death to come to us. We'll bring death, shiny sharp, to our enemies." —Krenko, mob boss
Wayne England
Magic 2013 (M13)
• #129Rulings
If an attacking creature loses haste, perhaps because Fervor leaves the battlefield after attackers have been declared, it won’t be removed from combat.
(wotc • 2012-07-01)
Rulings
If an attacking creature loses haste, perhaps because Fervor leaves the battlefield after attackers have been declared, it won’t be removed from combat.
(wotc • 2012-07-01)