It is narrated from Sayyiduna Samurah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A boy is held in pledge for his aqiqah; the aqiqah is to be offered on his behalf on the seventh day, he is to be given a name, and his head is to be shaved."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6925