Muwatta Malik, Book 9, Hadith 390 (In-Book)

Yahya related to me from Malik that he had heard that Said ibn al-Musayyab said, "It is said that no-one except a hypocrite leaves the mosque after the call to prayer, except for someone who intends to return."

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ، قَالَ يُقَالُ لاَ يَخْرُجُ أَحَدٌ مِنَ الْمَسْجِدِ بَعْدَ النِّدَاءِ - إِلاَّ أَحَدٌ يُرِيدُ الرُّجُوعَ إِلَيْهِ - إِلاَّ مُنَافِقٌ ‏.‏

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also referenced under: Book 9, Hadith 59 (USC-MSA)