Muwatta Malik 752

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ الْقَاسِمِ، عَنْ أَبِيهِ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، قَالَ يَا أَهْلَ مَكَّةَ مَا شَأْنُ النَّاسِ يَأْتُونَ شُعْثًا وَأَنْتُمْ مُدَّهِنُونَ أَهِلُّوا إِذَا رَأَيْتُمُ الْهِلاَلَ ‏.‏

Yahya related to me from Malik, from Abd ar-Rahman ibn al-Qasim, from his father, that Umar ibn al-Khattab said, "People of Makka, why is it that people arrive dishevelled while you still have oil on your hair? Go into ihram when you see the new moon

Reference

Muwatta Malik 752

In-book

Book 20, Hadith 48