وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ دَاوُدَ بْنِ الْحُصَيْنِ، قَالَ أَخْبَرَنِي مُخْبِرٌ، أَنَّ عَبْدَ اللَّهِ بْنَ عَبَّاسٍ، كَانَ يَقُولُ دُلُوكُ الشَّمْسِ إِذَا فَاءَ الْفَىْءُ وَغَسَقُ اللَّيْلِ اجْتِمَاعُ اللَّيْلِ وَظُلْمَتُهُ ‏.‏

Yahya related to me from Malik that Da'ud ibn al-Husayn said thatsomeone had told him Abdullah ibn Abbas used to say, "Duluk ash-shamsbegins from when the sun passes the meridian. Ghasaq al-layl is thegathering of the night and its darkness." Translation Not Available

Book Ref: Muwatta Imam Malik Book 1 Hadith 20
Web Ref:  Muwatta Imam Malik Book 1 Hadith 20