Qabus bin Abu Dhubyan reported,

We said to Ibn Abbas, "What do you make of the words of Allah , 'Allah has not placed within a man two hearts in his chest'? What was meant by that?"Ibn Abbas replied, "One day the Prophet of Allah ﷺ stood up to pray, and a thought crossed his mind. The hypocrites who were praying with him said, 'Do you not see that he has two hearts, one heart with you and one heart with them?' So Allah revealed , 'Allah has not placed within a man two hearts in his chest'."

حدثنا حسن حدثنا زهير

عن قابوس بن أبي ظبيان أن أباه حدثه قال

قلنا لابن عباس أرأيت قول الله عز وجل {ما جعل الله لرجل من قلبين في جوفه} ما عنى بذلك قال قام نبي الله ﷺ يوما يصلي قال فخطر خطرة فقال المنافقون الذين يصلون معه ألا ترون له قلبين قال قلب معكم وقلب معهم فأنزل الله عز وجل {ما جعل الله لرجل من قلبين في جوفه}