Began at the eldest, to take off all their suspicion of his fraud. The cup was found in Benjamin's sack. He found doubtless the money there, but he accused them not about that matter, both because they had an answer ready to that charge from his own mouth, Genesis 43:23, and because the greater crime, the stealing of the cup which Joseph so much prized and used, might seem to extinguish the less, or at least cause him to neglect it.
Related Commentaries of Genesis 44:12
Genesis 44:12
12 And he searched, and began at the eldest, and left at the youngest: and the cup was found in Benjamin's sack.