Muwatta Malik:Tahajjud:Hadith 261
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ، كَانَ يَقُولُ يُكْرَهُ النَّوْمُ قَبْلَ الْعِشَاءِ وَالْحَدِيثُ بَعْدَهَا ‏.‏

Yahya related to me from Malik that he had heard that Said ibn al-Musayyab used to say, “Sleep is disapproved of before isha and conversation after it.”