Is there a penalty for not fasting two months vowed before marriage, and must they be fasted consecutively or can they be non-consecutively?

A conditional vow is disliked, but it must be fulfilled if the condition is met, for the Prophet, peace and blessings be upon him, said: "Whoever vows to obey Allah, let him obey Him." This vow remains a responsibility as long as the vower is not unable to fast.

As for stipulating consecutive fasting in an absolute vow, the majority of scholars hold that it is not obligatory unless it was stipulated or a vow was made to fast for a specific period.

Therefore, if the two months were not specified, she may fast them consecutively or separately. If she fasts them according to the lunar months, fasting two months will suffice, even if a month is less than thirty days, provided she fasts them consecutively. However, if she does not fast according to the lunar months, she must fast sixty days.