Albert Barnes Commentary Luke 2:44

"but supposing him to be in the company, they went a day`s journey; and they sought for him among their kinsfolk and acquaintance:" — Luke 2:44 (ASV)

Supposing him to have been in the company. It may seem very remarkable that parents should not have been more attentive to their only son, and that they should not have been assured of his presence with them when they left Jerusalem; but the difficulty may be explained by the following considerations:

1. In going to these great feasts, families and neighbours would join together, and form a large collection.
2. It is not improbable that Jesus was with them when they were about to start from Jerusalem and were making preparations. Seeing him then, they might have been certain as to his presence.
3. A part of the company might have left before the others, and Joseph and Mary may have supposed that he was with them, until they overtook them at night and ascertained their mistake.

Kinsfolk. Relatives.

Acquaintances. Neighbours who had gone up with them in the same company to Jerusalem.