Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
suyuti:1816a
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السيوطي:١٨١٦a

"إِذَا ذَكرهَا فليُصَلِّها، وليُحْسنْ صلاتَه، وَليَتَوَضَّأ فليُحْسنْ وضوءَهُ، فذلك كفارتُه".  

[طب] الطبرانى في الكبير عن ميمونة بنت سعد

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Collected by Ṭabarānī
tabarani:21620Aḥmad b. al-Naḍr al-ʿAskarī > Isḥāq b. Zurayq al-Rāsibī

[Machine] She said, "O Messenger of Allah, advise us about a person who forgets to pray until the sun rises or sets, what should be done to atone for it?" He said, "If he remembers it, then let him pray it and perfect his prayer, and let him perform ablution and perfect his ablution, for that will be his atonement."  

الطبراني:٢١٦٢٠حَدَّثَنَا أَحْمَدُ بْنُ النَّضْرِ الْعَسْكَرِيُّ ثنا إِسْحَاقُ بْنُ زُرَيْقٍ الرَّاسِبِيُّ ثنا عُثْمَانُ بْنُ عَبْدِ الرَّحْمَنِ الطَّرَائِفِيُّ ثنا عَبْدُ الْحَمِيدِ بْنُ يَزِيدَ عَنْ آمِنَةَ بِنْتِ عُمَرَ بْنِ عَبْدِ الْعَزِيزِ عَنْ مَيْمُونَةَ بِنْتِ سَعْدٍ

أَنَّهَا قَالَتْ أَفْتِنَا يَا رَسُولَ اللهِ عَنْ رَجُلٍ نَسِيَ الصَّلَاةَ حَتَّى طَلَعَتِ الشَّمْسُ أَوْ غَرَبَتْ مَا كَفَّارَتُهَا؟ قَالَ «إِذَا ذَكَرَهَا فَلْيُصَلِّهَا وَلْيُحْسِنْ صَلَاتَهَا وَلْيَتَوَضَّأْ وَلْيُحْسِنْ وُضُوءَهُ فَذَلِكَ كَفَّارَتُهُ»