So – as a hypothetical example – every other history magazine can’t hold a candle to History Revealed.
It doesn’t take much to illuminate the origins of the phrase. The light of a single candle will do. Before electric lights, craftsmen would employ someone as a second pair of hands, chiefly to hold candles close enough so they could see what they were doing.
As this was not a skilled job – the candle-holding apprentices were usually children – it would have been a grievous insult for trainee craftsmen to be told they weren’t good enough even to hold the candle, let alone do the expert, highly-trained work of the actual craftsmen.