Christians are told Jesus came to serve, not be served. To follow Christ is to be like Him, follow His examples and serve others. As a kid that was a strange notion e because I equated service with being a servant–which of course, I was not. It took a while to realize one can serve without being a servant in the negative sense of the word.
Volunteering: there are so many ways this can be done for the purpose and glory to God. One of those is “Feed My Starving Children”. Jesus told his disciples they could do wonders with faith the size of a mustard seed.