Say not unto thy neighbour, Go, and come again, and tomorrow I will give; when thou hast it by thee.
In short pay your debts/bills when they come due. Do not delay to pay them or defer to pay them when you can. Very important Biblical financial advice for youth and adults alike. Stay out of debt, and pay off all debts as soon as you are able or required to do so.
Paying off your debts is the difference between a honest man and a thief and a free man and a slave. Which one are you?