What is your fatwa on brothers doing da`wah (دعوة) to other Muslim brothers instead of non-Muslim brothers considering that it's not a Sunnah?

Jazakom ALLAH Khairan

In the name of Allah, the Most Merciful, the Grantor of Mercy

All praise belongs to Allah, and may prayers and peace be upon Allah’s final Messenger.

Da’wah is given to both Muslims and no-Muslims, and the Prophet (peace and blessings be upon him) spent his entire life - after God commissioned him - in giving da’wah to all people.

Allah says:

" وَمَا أَرْسَلْنَاكَ إِلَّا كَافَّةً لِّلنَّاسِ بَشِيرًا وَنَذِيرًا وَلَكِنَّ أَكْثَرَ النَّاسِ لَا يَعْلَمُونَ"

“And We have not sent you but to all the men as a bearer of good news and as a warner, but most men do not know.” (Saba’ 34:28)

Allah knows best.

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