Daniel purposed in his heart— Daniel had two reasons for refusing the meat from the king's table: first, because the heathens ate indiscriminately all sorts of food, and consequently such as was forbidden by the law of Moses: the second, because it was the custom of most nations before their meals, to make an offering of some part of what they were to eat or drink to their gods: so that every entertainment had something in it of the nature of a sacrifice. This practice generally prevailing, made Daniel and his friends look upon the provisions coming from the king's table as no better than meats offered to idols, and consequently polluted and unclean. See Calmet.
Related Commentaries of Daniel 1:8
Daniel 1:8
8 But Daniel purposed in his heart that he would not defile himself with the portion of the king's meat, nor with the wine which he drank: therefore he requested of the prince of the eunuchs that he might not defile himself.