Is it permissible to work informally to pay off debts?

A Muslim is obligated to respect the laws of the countries he resides in, as long as they do not violate Islamic law. He must be a good role model of a sincere Muslim who adheres to covenants and trusts, as Allah Almighty says: "And those who are to their trusts and their covenants attentive," and "And fulfill the covenant of Allah when you have made a covenant, and do not break oaths after their confirmation." If a Muslim is prevented from working and cannot repay his debt, there is no blame upon him. He should firmly intend to repay the debt when funds become available, in accordance with the hadith: "Whoever takes people's money with the intention of repaying it, Allah will repay it on his behalf; and whoever takes it with the intention of destroying it, Allah will destroy him." It is also recommended to supplicate for the repayment of debt.