He said the campaign was serious about wanting change.
Mawarire was freed on Wednesday when a court in Harare dismissed a legal case against him.
His lawyers successfully argued that the charge of subversion had been added at the last minute, denying him a fair trial.
The pastor has been at the heart of a social media campaign denouncing the government’s management of the economy.
He said the #ThisFlag movement’s goal was to “get as many citizens as possible involved in nation-building”.
His latest call for people to stay away from work in protest at the economic crisis went largely unheeded, with most businesses opening as normal on Wednesday.
Mr Mawarire admitted the protest was not as successful as last week’s – when the country’s cities were deserted – but said the strike should continue on Thursday.
He said: “Let’s all shut down and send a message to our government that enough is enough, we need changes in very simple things, in very simple areas.
“And our protest – non-violent, non-inciting, stay-at-home, is the best because it is within the confines of the law.
“Every Zimbabwean who does not participate is robbing us of a great opportunity to add to the momentum of where our country is going.”