Take double the amount of silver with you, for you must return the silver that was put back into the mouths of your sacks. Perhaps it was a mistake.
NIV
And take double the [grain] money with you; and the money that was put back in the mouth of your sacks, carry it again with you; there is a possibility that [its being in your sacks] was an oversight.
AMP
And take double money in your hand; and the money that was brought again in the mouth of your sacks, carry it again in your hand; peradventure it was an oversight:
KJV