What is the ruling on a woman who vowed to perform prayers to ensure she would not abandon them, but then was unable to continue and stopped, and what is its expiation?

Prayer is the second pillar of Islam and the first thing a servant will be held accountable for on the Day of Judgment. One who abandons it is threatened with woe and ruin. Some scholars have gone so far as to declare one who abandons prayer out of laziness to be an unbeliever, based on Prophetic hadiths such as, "Between a man and disbelief and polytheism is the abandonment of prayer." One who abandons prayer must repent and hasten to establish it. As for vows related to prayer, they are not binding, because prayer is an obligation in the first place.