Does debt prevent a supplication from being answered, and is expiation for an oath—such as feeding ten needy persons—or any other expiation considered part of the debt that prevents a supplication from being answered?

For a supplication to be answered, there are conditions and causes, and there are also impediments. Debt, if its owner is not procrastinating in repaying it, does not prevent the supplication from being answered. However, if he is procrastinating despite his ability, this may prevent the answer; because procrastination is an injustice and a sin, and sins prevent the supplication from being answered. Evidence for this includes the Prophet's (peace be upon him) saying: "Procrastination by a wealthy person is an injustice that makes his honor and punishment permissible," and Allah's (the Most High) saying: "Indeed, Allah only accepts from the righteous." Allah may answer the supplication of a sinner as a favor from Him, or as a gradual enticement for him.