What proof is there from the Quran and Hadith with regards to issuing 3 Talaaqs?

Answer:

In the Name of Allah, the Most Gracious, the Most Merciful.

As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh. 

If a person issues his wife three divorces in one sitting or three divorces in separate sittings, that will constitute three divorces which will terminate the marriage irrevocably (talaq-e-mughallazah). It is interesting to note that this is also the view of Imam Bukhari Rahimahullah. You may refer to our research on the issue on the following link.

http://askimam.org/public/question_detail/17287

And Allah Ta’āla Knows Best

Abdul Hannan Nizami,
Student Darul Iftaa
Chicago, USA 

Checked and Approved by,
Mufti Ebrahim Desai.