What did the three days of examining the Passover lamb picture?
The three days of examining the Passover lamb pictured the three years of Christ's earthly ministry. During that time He was examined and proved to be without blemish or spot, fully worthy to be offered as the Passover lamb. The scrutiny confirmed His perfection, just as the lamb had to be perfect.
Les explains that the Passover lamb was brought and kept until the 14th, which amounted to three full days. They examined it daily to make sure there was no blemish; if the slightest thing was wrong, they had to reject it. If after three days of scrutiny they were satisfied it was perfect and without blemish, they could offer it as their Passover lamb. The picture was that those three days were comparable to His three years of earthly ministry, where He also proved Himself without blemish. As 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.