Strong's 3784 (ὀφείλω)

behove, be bound, (be) debt(-or), (be) due(-ty), be guilty (indebted), (must) need(-s), ought, owe, should

to owe (pecuniarily); figuratively, to be under obligation (ought, must, should); morally, to fail in duty

probably from the base of G3786 (ὄφελος) (through the idea of accruing);