What is the ruling on a debtor delaying the repayment of a loan despite being well-off, claiming insolvency, and does the passage of time affect the ruling on the debt?

It is not permissible for a debtor who is able to pay to delay settling a debt when its owner demands it, once it has become due, because this constitutes prohibited injustice, as the Prophet, peace and blessings be upon him, said: "The delay in payment by a rich person is injustice." The creditor has the right to demand the debt from the debtor, even by resorting to legal action.