What is the ruling for someone who made a vow to Allah, then forgot what they vowed?

A vow of obedience that is conditional upon the occurrence of a certain event must be fulfilled once that condition is met, for the Prophet, peace and blessings be upon him, said: "Whoever vows to obey Allah, let him obey Him." However, if one forgets the condition upon which the vow was suspended, then nothing is incumbent upon him, because the default is the absolution of responsibility, and fundamental principles are not removed by doubt. This is similar to cases of divorce that are made conditional upon an event and then forgotten; divorce does not occur due to doubt.