Muwatta Malik Book 7, Hadith 33
Yahya related to me from Malik from Abd ar-Rahman ibn al-Qasim
that al-Qasim ibn Muhammad had done the same as Ibn Umar.
Yahya related to me from Malik that he had heard that Abdullah ibn Umar missed the two rakas of dawn, and then did them after the sun rose.
Yahya related to me from Malik from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, said, "Prayer in congregation is better than the prayer of a man by himself by twenty-seven degrees."