What should Da`wah (calling to Islam) priorities be; doing charitable deeds, such as building Masjids (mosques) and helping the afflicted, or calling governments to apply Shari`ah (Islamic law) and fighting against all forms of corruption?
The duty of scholars is to follow the example of messengers (peace be upon them) who started their Da`wah with Kafir (disbelieving) groups and non-Muslim countries. This is through calling to Tawhid (belief in the Oneness of Allah), abandoning worship of anything apart from Allah, believing in Him, confirming His Names and Attributes in a way that most befits Him, believing in His Messenger (peace be upon him), loving him and following him. In addition, scholars should call Muslims everywhere to adhere and hold fast to Shari`ah, advise rulers and help and relieve the needy. Moreover, while continuing with their Da`wah efforts, scholars should not neglect doing charitable deeds. They can visit rulers, praise their righteous deeds and encourage them to apply Shari`ah and bind nations to apply it.
But no, by your Lord, they can have no Faith, until they make you (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭﺳﻠﻢ) judge in all disputes between them, and find in themselves no resistance against your decisions, and accept (them) with full submission.
Do they then seek the judgement of (the days of) Ignorance? And who is better in judgement than Allâh for a people who have firm Faith.
There are many Ayahs (Qur'anic verses) to the same effect.