Angelic Benediction (ALA) from Shards of Alara, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Michael Komarck
• Card Text:
  Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
  Whenever a creature you control attacks alone, you may tap target creature.