Unwashable sins

Place this Enchantment on a creature. When that creature attacks;
• a creature with a mana score of 4 or higher
•or an opposing player.
It can no longer attack while this enchantment is played on it.
'Will all great Neptune's ocean wash this blood clean from my hand? No, this my hand will rather the multitudinous seas incarnadine, making the green one red'-Macbeth Act II scene II