Fergusson was a friend of Robert Burns and the victor of the drinking match immortalised in his poem "The Whistle". He was also a Justice of the Peace. In this letter Burns requests Fergusson's assistance for "poor Robie Gordon", a man he is about to prosecute in the course of his official duties.
This is a piece of red-hot poetic indignation roused on behalf of one of the unfortunate for whom Burns was always ready to do battle, however backward he was to plead his own case.