And when he was twelve years old, they went up to Jerusalem according to the custom of the feast.
All Commentaries on Luke 2:42 Go To Luke 2
Ambrose of Milan
AD 397
Or the twelfth year was the commencement of our Lord's disputation with the doctors, for this was the number of the Evangelists necessary to preach the faith.
After three days He is found in the temple, that it might be for a sign, that after three days of victorious suffering, He who was believed to be dead should rise again ant manifest Himself to our faith, seated in heaven with divine glory.
There are two generations in Christ, one from His Father, the other from His mother; the Father's more divine, the mother's that which has come down for our use and advantage.