A.T. Robertson Commentary Luke 2:41

"And his parents went every year to Jerusalem at the feast of the passover." — Luke 2:41 (ASV)

Every year (κατ' ετος). This idiom only here in the N.T., a common Greek construction. Every male was originally expected to appear at the passover, pentecost, and tabernacles (Exodus 23:14–17; Exodus 34:23; Deuteronomy 16:16). But the Dispersion rendered that impossible. But pious Palestinian Jews made a point of going at least to the passover. Mary went with Joseph as a pious habit, though not required by law to go.