Why did Jesus prove himself worthy to be the Passover lamb?
Jesus proved Himself worthy to be the Passover lamb through His three years of earthly ministry, which corresponded to the three-day examination of the lamb. He was without blemish, never sinned, and was impeccable, as Paul says, "He who knew no sin."
Les explains that the Passover lamb was brought up and kept until the 14th, giving three full days to examine it for any blemish. If the slightest thing was wrong, it had to be rejected. But if after three days it was found perfect and without blemish, it could be offered as the Passover lamb. That pictured Christ's three years of earthly ministry, during which He also proved Himself without blemish. Paul says He who knew no sin never sinned. His three years were impeccable, and He proved Himself worthy to be the Passover lamb, a lamb without blemish and without spot.