Make not the devil blacker than he is.

Understand the thought

Meaning in plain English

Do not exaggerate a fault or make an already troubling situation seem worse than the evidence shows. The devil supplies an extreme image, but the practical point is proportionate judgement rather than denying real wrongdoing.

What the words are saying

The saying objects to adding more darkness to a figure already presented as bad. Figuratively, a complaint can grow through repeated telling until assumptions and embellishments are treated as facts. A useful response separates what is known from what is inferred and describes the actual problem accurately. That allows criticism to remain serious without acquiring unsupported accusations. The proverb should not silence someone who reports harm or require a cheerful account of misconduct. Nor does it establish a religious claim about the devil. Its emphasis is proportion: assess the conduct at issue without adding faults merely because the person or situation is already disliked.

Everyday example

A reader finds one incorrect label in a display and reports that error rather than telling others that every item in the collection is unreliable.

When to use it

Use it when criticism is becoming broader than the available evidence.

Agent-assisted editorial interpretation. This explains the words; it does not by itself verify their author or earliest origin.