One must sometimes hold a candle to the devil.

Circumstances may force someone to help or accommodate a person they consider objectionable. Holding the candle suggests serving that person, even while disapproving of them.

The proverb treats such cooperation as a reluctant practical choice, not necessarily a sign of loyalty or approval. Its emphasis is on the pressure created by necessity: sometimes refusing to help is not a workable option.

Use this proverb when someone feels obliged to assist or make concessions to a person whose conduct they disapprove of. It fits a situation of uneasy cooperation better than one of willing support.