It was narrated that Abdur-Rahman bin Yamur said:"I saw the Messenger of Allah when people came to him and asked him about Hajj. The Messenger of Allah said: 'Hajj is Arafat. Whoever catches up with the night of Arafat before dawn comes on the night of Jam (Al-Muzdalifah), his Hajj is complete.'"
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا وَكِيعٌ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ بُكَيْرِ بْنِ عَطَاءٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ يَعْمَرَ، قَالَ شَهِدْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم فَأَتَاهُ نَاسٌ فَسَأَلُوهُ عَنِ الْحَجِّ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْحَجُّ عَرَفَةُ فَمَنْ أَدْرَكَ لَيْلَةَ عَرَفَةَ قَبْلَ طُلُوعِ الْفَجْرِ مِنْ لَيْلَةِ جَمْعٍ فَقَدْ تَمَّ حَجُّهُ " .
Nesai
The Book of Hajj • Hadith 3016