وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، وَعُثْمَانَ بْنَ عَفَّانَ، كَانَا يُصَلِّيَانِ الْمَغْرِبَ حِينَ يَنْظُرَانِ إِلَى اللَّيْلِ الأَسْوَدِ قَبْلَ أَنْ يُفْطِرَا ثُمَّ يُفْطِرَانِ بَعْدَ الصَّلاَةِ وَذَلِكَ فِي رَمَضَانَ ‏.‏

Yahya related to me from Malik from Ibn Shihab from Humayd ibnAbd ar-Rahman that Umar ibn al-Khattab and Uthman ibn Affan would praymaghrib when they saw the night darkening, before they broke theirfast, and that was during Ramadan. Translation Not Available

Book Ref: Muwatta Imam Malik Book 18 Hadith 641
Web Ref:  Muwatta Imam Malik Book 18 Hadith 8