 Only those who were circumcised and clean before the Law might participate, and they were forbidden to have leavened food in their possession during the act of killing the Passover lamb.The animal was slain on the eve of the Passover, on the afternoon of the 14th of Nisan, after the Tamid sacrifice had been killed, i.e., at three o'clock, or, in case the eve of the Passover fell on Friday, at two.The sacrificial service took place in the courtyard of the Temple at Jerusalem.