Sunan Abi Dawud 4356
سنن أبي داود#4356SahihAbu Burdah said:A man who turned back from Islam was brought to Abu Musa. He invited him to repent for twenty days or about so. Muadh then came and invited him (to embrace Islam) but he refused. So he was beheaded
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih Isnaad
Muhammad Muhyi Al-Din Abdul HamidSahih Isnaad
Shuaib Al ArnautSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 40:6