Is it obligatory to fulfill a vow by slaughtering a sheep when the desired outcome is achieved, or is paying off debts and completing marriage more prioritized?

Fulfilling a vow (nadhr) is obligatory in the manner in which it was vowed, based on the Almighty's saying: ﴿And let them fulfill their vows﴾ (22:29), and the Prophet, peace and blessings be upon him, said: "Whoever vows to obey Allah, let him obey Him."

If the vow is not time-bound, there is no harm in delaying its fulfillment, because fulfilling a vow is not immediately obligatory according to the most sound opinion, unless its wording necessitates immediacy.

However, if it is time-bound to a specific time, then it is obligatory to fulfill it within its designated time. Delaying it, while being able to fulfill it, entails sin, an expiation for breaking an oath (kaffarat yameen), and its fulfillment thereafter.