Genesis 44:2

Joseph now shows his wisdom in a way that leads his brothers to repentance without accusing them. He told his steward to fill their sacks with food and put their money back in the sacks again. On top of that, he tells him to put his own silver cup in the mouth of Benjamin's sack. The next morning they were on their way, no doubt rejoicing that this time everything had gone so well.

He will give them a feast, but in such a way that they cannot help seeing that their history is known… But before Joseph can reveal himself to them, they must be exposed before Joseph. That is why Joseph's cup is put in Benjamin's sack.

This place, this moment, was the field of Dothan again. In spirit they were going back to the place where they had committed the whole offence. In the field of Dothan, in Gen. 37, they had to answer this: would they sacrifice their innocent brother Joseph to their lusts, their envy and their malice? Now Benjamin is claimed as a prisoner because of the cup found in his sack — claimed as one who has forfeited his life and liberty to the lord of Egypt. In the same way the question is put to them: would they sacrifice him too, and go on home, easy and careless and satisfied?

Joseph's silver cup was in one of their sacks, so they had to come back… Tell me, what iniquity was there in relation to the cup? None; but it served to rouse conscience. It brought up the twenty pieces of silver, and the wickedness of their history in days gone by.

The cup is a symbol of a verdict: the ruler of the feast decided who received it, in what order, and what it held… A judging or "divining cup" was a common thing among ancient peoples, and Joseph points to that idea in Gen. 44:15. Now this cup may hold either happiness or condemnation.

It would be hard to make me believe that Joseph used magic at all, and that is the idea behind divining here. I have very little doubt that Joseph was hiding who he really was. He gave them the impression that he was skilled in the magic arts of the Egyptians, and was nothing other than an Egyptian lord… He did not use the cup to reach his brothers' affections, but as a way of reaching their consciences.

Severe as the trial was, love prompted it in the fear of God. Still, we may feel that the method he used was in no way what the New Testament would suggest to a Christian… Joseph acted according to his own measure, weakened no doubt by the Egyptian life that surrounded him. Scripture tells us the facts as they were, without approving them or excusing them… And the steward knew well what his master intended.

This is what led to the cup in Benjamin's sack. No doubt the shock of finding it there deeply troubled the brothers… After all, the pain of the method used was very short, and the same day brought forgiveness, joy and tender love.