A pauper's oath is a sworn statement or oath by a person that he or she is completely destitute or a pauper, i.e. without any money or property
1984 London
It was a very poor person in the 18->19th century,they had to work in workhouses to have a bed and a small bit of food,Oliver Twist was a pauper
He is courageous, bold, honest, trustworthy, loyal.
pobre, indigente
It is the Hippocratic Oath, inspired by an ancient Greek physician named Hippocrates.