Repeating a prayer in congregation

Repeating a prayer in congregation when one has already prayed either alone or in congregation

من أدى الصلاة المكتوبة منفردا ثم وجد جماعة استحب له أن يدخل مع الجماعة لتحصيل الفضل

The person who has prayed the obligatory prayer alone then he comes to a congregation [taking place for that obligatory prayer], it is recommended for him to join the congregation to get extra reward.

لما ورد عن رسول الله صلى الله عليه وسلم أنه صلى في مسجد الخيف، فرأى رجلين خلف الصف لم يصليا معه، فقال: علي بهما، فجيء بهما ترعد فرائصهما، فقال: ما منعكما أن تصليا معنا؟ فقالا: يا رسول الله: إنا كنا قد صلينا في رحالنا، قال: فلا تفعلا، إذا صليتما في رحالكما ثم أتيتما مسجد جماعة، فصليا معهم، فإنها لكما نافلة

Based on that which has been narrated from the Messenger of Allaah (sallallaahu alayhi wa sallam)

Narrated Yazid ibn al-Aswad:

Yazid prayed along with the Messenger of Allah (sallalalahu alayhi wa sallam) when he was a young boy. When he (the Prophet) had prayed there were two persons (sitting) in the corner of the mosque; they did not pray (along with the Prophet). He called for them. They were brought trembling (before him). He asked: What prevented you from praying along with us? They replied: We have already prayed in our houses. He said: Do not do so. If any of you prays in his house and finds that the imam has not prayed, he should pray along with him; and that will be a supererogatory prayer for him.

[Sunan Abu Dawud Hadith No. 575]

وهذا باتفاق، من حيث طلب الإعادة لتحصيل الفضل - وللفقهاء تفصيل في استثناء بعض الصلوات من استحباب الإعادة

This point is a point of agreement among the jurists so far in as attaining virtue by means of repeating the prayer in congregation. The Jurists then go into detail of making an exception to certain prayers when it comes to repeating them.

الحنفية والمالكية والحنابلة لا تعاد صلاة المغرب؛ لأن التنفل بالثلاث بعد المغرب مكروه

The Hanafi, Maaliki, and Hanbali schools of thought say that one is not to repeat al-Maghrib prayer because praying a Nafl prayer which consists of three Rak'ah after al-Maghrib is makruuh.

وزاد الحنفية عدم إعادة العصر والفجر؛ لكراهة النفل بعدهما، وهو محكي عن بعض الشافعية

The Hanafi add to this that one is not to repeat al-Asr and al-Fajr prayers because praying Nafl after these two prayers is makruuh. This opinion is also transmitted from some belonging to the Shaafi'i school of thought.

وقال المالكية: لو أوتر بعد العشاء فلا يعيد العشاء

And the Maaliki school has said: If one has performed al-Witr after al-'ishaa then he will not repeat al-'ishaa in congregation if he finds a congregation performing al-'ishaa.

ابن عابدين 1 / 479، 480
البدائع 1 / 287
الهداية مع شروحها فتح القدير والعناية 1 / 412
الحطاب 2 / 84 - 85
المهذب 1 / 102
أسنى المطالب 1 / 212
المغنى 2 / 111 - 113
كشاف القناع 1 / 458
الموسوعة الفقهية الكويتية 27 / 174