Musnad Ahmad 25:385

'Abdullah ibn Maymun Abu 'Abd al-Rahman al-Raqqi narrated to us, he said: Al-Hasan—meaning Abu al-Malih—informed us, from Habib—meaning Ibn Abi Marzuq—from 'Ata', from Ibn 'Abbas, he said: "Whoever arrives as a pilgrim (Hajj), and performs Tawaf around the House, and [performs] between al-Safa and al-Marwah, his Hajj has ended and it has become an 'Umrah. Such is the Sunnah of Allah, the Almighty and Majestic, and the Sunnah of His Messenger, may Allah bless him and grant him peace."