Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: It was asked from the Prophet Muhammad (peace be upon him) about a person who shaves his head before sacrificing (the animal), or who sacrifices the animal before throwing (the pebbles). The Prophet Muhammad (peace be upon him) kept saying: There is no sin in it.
Hadith Referenceصحیح ابن حبان / كتاب الحج / 3876
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «صحيح أبي داود» (1731): ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط الشيخين