Blessing of the Pure

When this permanent enters the battlefield
enchant target land you control. The Enchanted
land gains the following effects
{t} - Add {w}{w} to your mana pool.
{t}{w} - Summon one 3/3 Pure Knight Token
with Vigilance
{t}{w}{w}{w}{w}{w} - Sacrifice this enchantment
gain 10 life.