How long did the Israelites have to keep and inspect the Passover lamb before they could kill it?

Les teaches that the Passover lamb was kept up for three days to be completely observed. During that time, the household was to look for any blemish, any sign of poor health, or anything wrong with it. If at the end of those three days the lamb was whole, they could kill it for the Passover sacrifice. Les explains that this pictures Christ, who spent three years up and down the land of Israel under complete scrutiny by the religious authorities and ordinary people. He was not hidden from anyone, yet no one could point a finger at Him and accuse Him of wrongdoing. He was without spot, without blemish, blameless. After the lamb was proved, they took its blood and struck it on the two sides and on the upper doorpost of the houses where they would eat it. They ate the flesh that night roasted with fire, not raw or boiled in water. Les sees the fire as indicative of judgment, just as Christ went through the fires of judgment on the cross to bring about salvation. The lamb was not to be fixed any other way, because this indicated judgment.