Daniel 1:5 and 8

"And the king appointed for them a daily provision of the king's delicacies and of the wine which he drank, and three years of training for them, so that at the end of that time they might serve before the king."

"But Daniel purposed in his heart that he would not defile himself with the portion of the king's delicacies, nor with the wine which he drank; therefore he requested of the chief of the eunuchs that he might not defile himself."