John Gills Exposition of the Bible Commentary

Verse 8 (Daniel 1:8)

But Daniel purposed in his heart ,.... It being proposed to him to be brought up in the manner before described, he revolved it in his mind; he well weighed it, and considered it with himself, and came to a resolution about it. This is to be understood of him, not to the exclusion of his three companions, who were of the same mind with him, as appears by what follows; but perhaps it was first thought of by him; at least he first moved it to them, to which they consented; and because he was the principal in this affair, it is ascribed to him as his purpose and resolution:

that he would not defile himself with the portion the king's meat ; by eating of it; partly because it might consist of what was forbidden by the law of Moses, as the flesh of unclean creatures, particularly swine, and fat and blood, and so defile himself in a ceremonial sense; and partly because, though it might be food in itself lawful to be eaten, yet part of it being first offered to their idol "Bel", as was usual, and the whole blessed in his name, it would have been against his conscience, and a defiling of that, to eat of things offered to, or blessed in the name of, an idol:

nor with the wine which he drank ; which was as unlawful as his food; being a libation to his gods, as Aben Ezra observes; otherwise wine was not forbidden; nor was it disused by Daniel, when he could partake of it in his own way, Daniel 10:3 ,

therefore he requested of the prince of the eunuchs that he might not defile himself ; he did not, in a surly, still, and obstinate manner, refuse the meat and drink brought; but prudently made it a request, and modestly proposed it to the prince of the eunuchs, that had the care and charge of him and his companions; and who also joined with him in this humble suit, as appears by what follows.

- John Gills Exposition of the Bible Commentary