"To join the rally" means to actively participate or be a part of a gathering or demonstration where people come together to support a cause or express their opinions. Full definition
Traders have also joined rallies in different parts of Pakistan who say that power crisis has badly affected their business. (dotearth.blogs.nytimes.com)
Author Frank Viola joined the rally with a fantastic post entitled «Rethinking Christian Unity» (rachelheldevans.com)
Hundreds of teachers from central New York joined a rally in Albany this weekend to continue pressing the state for change. (wrvo.org)