Answered by Ustadha Zaynab Ansari, SunniPath Academy Teacher
If one has prayed their fard prayer in private and then there is a jama’ah for the same prayer, is one obliged to pray with the jama’ah nullifying one’s prayer alone? What is the ruling for women in the Shafi’i school on this matter?
In the name of Allah, Most Compassionate, Most Merciful,
According to the Shafi’i school, your fard prayer is still valid. If there is a jama’ah after you have prayed alone, you are not obliged to join it. If you do join it, the prayer that you prayed alone is still valid. This applies to both men and women.
So for example, suppose you pray `asr alone and then people come and form a jama’ah. Whether you are male or female, it is recommended for you to join that congregation, but it is not obligatory. If you join them, you make intentions to repeat your `asr prayer, for example, and you get the reward of having performed a nafilah (supererogatory) prayer. [Reliance of the Traveller, 179]
And Allah knows best.