What are 2 ways that Holden protected Phoebe in The Catcher in the Rye?

One of the central themes in The Catcher in the Rye is Holden's desire to protect the innocence of childhood. In this way, his relationship with his younger sister, Phoebe, is pivotal to the story.
Holden often confides in Phoebe and believes she is one of the few people in his world that isn’t a “phony.” In one scene, Holden reveals his innermost desire:

That’s all I’d do all day. I‘d just be the catcher in the rye and all. I know it’s crazy, but that’s the only thing I’d really like to be.

The catcher in the rye is someone who stands guard to catch children before they might fall. This image symbolically describes Holden’s fixation on preserving innocence.
Two examples of Holden preserving innocence occur as Holden attempts to protect his younger sister. In one occasion, Holden desperately tries to erase swear words written on a wall at the school Phoebe attends. He doesn’t want her exposed to that type of language. In a later scene, Phoebe packs a suitcase and decides she wants to run away with Holden. He cannot allow this and convinces Phoebe that she must stay, distracting her by spending the day at the zoo with her instead.
It can be noted that in many ways, Phoebe also saves Holden. While watching the sweet and innocent Phoebe riding on a carousel, Holden is pulled out of his depression (at least momentarily). Phoebe gives Holden purpose.