"Qabus bin Abi Zabyan narrated to us, that his father narrated to him, he said: 'We said to Ibn 'Abbas: "What is the meaning of the saying of Allah the Mighty and Sublime: Allah has not made for any man two hears inside his body.? (33:4)" He said: "The Prophet of Allah ﷺ stood one day for Salat, then he was unsure (regarding how much he had prayed). The hypocrites who prayed with him said: 'Don't you see that he has two hearts, a heart with you and another with them?' So Allah revealed: 'Allah has not made for any man two hearts inside his body.'" (Using translation from Tirmidhī 3199)
قَالَ قُلْتُ لِابْنِ عَبَّاسٍ قَوْلَ اللَّهِ ﷻ {مَا جَعَلَ اللَّهُ لِرَجُلٍ مِنْ قَلْبَيْنِ فِي جَوْفِهِ} [الأحزاب 4] مَا عَنَى بِذَلِكَ؟ قَالَ قَامَ نَبِيُّ اللَّهِ ﷺ فَخَطَرَ خَطْرَةً فَقَالَ الْمُنَافِقُونَ الَّذِينَ يُصَلُّونَ مَعَهُ أَلَا تَرَوْنَ لَهُ قَلْبَانِ قَلْبٌ مَعَهُمْ وَقَلَبٌ مَعَكُمْ؟ فَأَنْزَلَ اللَّهُ ﷻ {مَا جَعَلَ اللَّهُ لِرَجُلٍ مِنْ قَلْبَيْنِ فِي جَوْفِهِ} [الأحزاب 4]