Fervor
Enchantment
Creatures you control have haste. (They can attack and 
as soon as they come under your control.)
The intensity of their glare was soon surpassed by the intensity of their attack.
Wayne England
Seventh Edition (7ED)
• #181★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)
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)