To wage jihad. Imposing sharia on areas where it was not previously imposed is a form of jihad even if no kuffar are killed in the process.
Jihad is not necessarily always violent. Any act which promotes Islam and sharia is jihad. Any act which intimidates people into not opposing Islam is jihad. Jihad can include violence, bribery, political agitation, lawsuits — whatever works. See my FR homepage for details.
They will be ceaseless in waging Jihad in all forms until they either give up Islam or are exterminated.