Damage dealt by a source with lifelink causes that source's controller, or its owner if it has no controller, to gain that much life (in addition to any other results that damage causes). See rule 119.3.
June 17, 2011 · Commander 2011
Damage dealt by a source with lifelink causes that source’s controller, or its owner if it has
April 1, 2011 · Duel Decks: Knights vs. Dragons
A permanent or player with protection can't be targeted by spells with the stated quality and can't be targeted by abilities from a source with the stated quality.
February 4, 2011 · Mirrodin Besieged
A permanent or player with protection can’t be targeted by spells with the stated quality and can’t be targeted by abilities from a source with the stated quality.
October 1, 2010 · Scars of Mirrodin
A permanent or player with protection can’t be targeted by spells with the stated quality
February 1, 2010 · Worldwake
A permanent or player with protection can't be targeted by spells with the stated quality and can't be targeted by abilities from a source with the stated quality.