Nursery Wonders

Origin and History to the words of Jack be nimble
The most commonly agreed origin for the Jack be nimble rhyme is the connection to Black Jack, an English pirate who was notorious for escaping from the authorities in the late 16th century hence Jack be nimble... The words of the Jack be nimble rhyme cannot be further analysed due to the brevity of the text of the lyrics but could be associated with the old tradition and sport of 'candle leaping' which used to be practised at some English fairs.

[Source rhymes.org.uk]