Householders keep dogs to guard their homes by barking when they hear
suspicious sounds outside. Figuratively, ‘to keep a dog and bark yourself’ is
to do the work that you pay others to do for you.

> ‘Isn’t it about time you clipped the front hedge, Henry?’ asked his wife.

> ‘That’s the gardener’s job’ he answered. ‘Why should I keep a dog and bark
myself?’