In your sentence, "all" is a pronoun. It restates "we" and acts as an intensifier so that the reader knows that "we" refers to more than just a small group.
- Being or representing the entire or total number, amount, or quantity: All the windows are open. Deal all the cards. See synonyms at whole.
- Constituting, being, or representing the total extent or the whole: all Christendom.
- Being the utmost possible of: argued the case in all seriousness.
- Every: got into all manner of trouble.
- Any whatsoever: beyond all doubt.
- Pennsylvania. Finished; used up: The apples are all. See Regional Note at gum band.
- Informal. Being more than one: Who all came to the party? See Regional Note at you-all.
The whole of one's fortune, resources, or energy; everything one has: The brave defenders gave their all.
- The entire or total number, amount, or quantity; totality: All of us are sick. All that I have is yours.
- Everyone; everything: justice for all.
- Wholly; completely: a room painted all white; directions that were all wrong.
- Each; apiece: a score of five all.
- So much: I am all the better for that experience.