Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated from the Messenger of Allah (peace and blessings be upon him) that he was asked (on the occasion of Hajj) about offering sacrifice, shaving the head, and the order of performing the stoning of the Jamarat, whether they could be done earlier or later, so the Prophet (peace and blessings be upon him) said: "There is no harm."
Hadith Referenceمسند اسحاق بن راهويه / كتاب المناسك / 343
Hadith Takhrij«مسلم ، كتاب الحج ، باب من حلق قبل النحر الخ ، رقم : 1306 . سنن ابوداود ، رقم : 1983 . سنن ترمذي ، رقم : 916 . سنن ابن ماجه ، رقم : 3050 . مسند احمد : 310/1 . سنن كبريٰ بيهقي : 446/2»
Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated from the Messenger of Allah (peace and blessings be upon him) that a questioner asked him, so he said: I shaved my head before slaughtering the sacrificial animal. The Messenger of Allah (peace and blessings be upon him) said: "Slaughter (now), there is no harm." He said: I performed Tawaf before Rami. The Messenger of Allah (peace and blessings be upon him) said: "(Now) perform Rami, there is no harm."
Hadith Referenceمسند اسحاق بن راهويه / كتاب المناسك / 344
Hadith Takhrij«بخاري، كتاب الحج، باب الحلق قبل الذبح، رقم: 1721. سنن ابي داود، رقم: 1983. سنن نسائي، رقم: 3067. سنن ابن ماجة، رقم: 3050»