I prayed and then discovered I was without wudu'; what should I do?
Short answer
A prayer without purity from minor impurity is not valid, and whoever remembers that he prayed without wudu' repeats that prayer.
Evidence and explanation
The Shaykh ruled to repeat the prayer when one remembers that it was performed without wudu'.
Scholar referenced
This editorial summary is based on the original source linked below and is not presented as a verbatim quotation from the scholar.
From the text of the answer (Arabic, with an English translation)
Original answer — Shaykh ‘Abd al-‘Aziz ibn Baz
حكم من صلى بغير وضوء ناسيًا فتذكر — فتوى ١٠١٥٨- Question
«أسأل سماحتكم عن صلاة صليتها، وتذكرت أنني صليتها بدون وضوء، كيف أتصرف؟»
English translation (unreviewed): I ask your eminence about a prayer that I prayed, and I remembered that I prayed it without wudu'. How do I proceed?
- From the text of the answer
«عليك أن تقضيها، متى ذكرت ذلك عليك أن تقضيها، نعم.»
English translation (unreviewed): You must make it up. Whenever you remember that, you must make it up. Yes.
The Arabic excerpts matched the original page word for word by an automated check and have not had human scholarly review. The English translations are unreviewed translations made for this site; they are not an approved Shari‘ah translation. Rely on the Arabic original.
Source
Ruling on one who prayed without wudu' forgetfully and then remembered
Title of the original page (Arabic): حكم من صلى بغير وضوء ناسيًا فتذكر
Shaykh ‘Abd al-‘Aziz ibn Baz, may Allah have mercy on him