Nafi' narrates from Ibn Umar (may Allah be pleased with them both): Whoever among the pilgrims reaches the Night of Sacrifice and stands on the mountains of Arafah before the dawn rises has attained the Hajj, and whoever does not reach the standing at Arafah before the dawn rises has missed the Hajj. He should come to the House and perform seven circuits, and perform sa'y between Safa and Marwah seven times, then shave his head or shorten his hair if he wishes. If he has his sacrificial animal with him, he should slaughter it before shaving; then when he has finished his tawaf and sa'y, he should shave or shorten his hair, and then return to his family. If the days of Hajj reach him the following year and he has the ability, that is, provision for the journey, he should perform Hajj and offer a sacrifice. If a sacrificial animal is not available, he should fast three days during the days of Hajj and seven days after returning home.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9820