Exodus 12:6

Keep it up until the fourteenth day] This is to ensure that no blemish shall pass undetected. In the evening] lit. 'between the evenings,' i.e. probably between sunset and darkness. Darkness was supposed to begin when three stars became visible. Josephus says that the time of sacrifice was from three to five in the afternoon. Observe that the Passover lamb was sacrificed and the blood sprinkled on the doorposts by each head of a household, there being at this time no tabernacle nor order of sacrificing priests. In later times the lamb was killed in the temple court by the head of the household and the blood poured out at the altar, after which the lamb was carried home to be eaten: cp. Leviticus 17:3; Deuteronomy 16:5.