Allah is pure and accepts only what is pure

On the authority of Abu Hurayra (may Allah be pleased with him), that the Messenger of Allah (may Allah bless him and grant him peace) said: "Allah is Good and accepts only what is good. Allah has commanded the believers with what He commanded the messengers. Allah the Exalted said: “O messengers, eat of the good things and do righteous deeds.” And Allah the Exalted said: “O you who believe, eat of the good things We have provided you.” Then he mentioned a man, dusty and dishevelled, long upon the road, who stretches out his hands to the sky: “My Lord! My Lord!” — yet his food is unlawful, his drink unlawful, his clothing unlawful, and he was nourished on the unlawful. How then should he be answered?"

Related by Muslim.

[Muslim 1015]