Firesong and Sunspeaker

If a white instant or sorcery spell you don't control causes you to gain life, Firesong and Sunspeaker's last ability triggers.

A spell causes you to gain life if its cost or effect instructs you to gain life or if an instruction in its cost or effect is modified by a replacement effect and the modified event includes you gaining life. If a spell's cost or effect instructs a source with lifelink you control to deal damage, that spell causes that life gain as well.

If you gain an amount of life "for each" of something, that life is gained as one event and Firesong and Sunspeaker's last ability triggers only once.