Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with them both) narrates that while the Prophet Muhammad (peace be upon him) was delivering the sermon on the Day of Sacrifice, a man stood before him and said, "O Messenger of Allah, I did not know that such-and-such act comes before such-and-such act." Then another man said, "O Messenger of Allah, I did not know that among these three acts (stoning, shaving the head, and sacrificing), such-and-such act comes first and such-and-such comes after." The Prophet (peace be upon him) said: "Whatever remains, do it, and there is no harm." This narration is from Isa, and in the narration of Ibn Ma'mar, there is this addition: that whatever was asked of you that day (regarding the order of these acts), you said: "There is no harm, now do (whatever remains)."