Answered by Shaykh Yusuf Weltch
Question
Unfortunately, I broke my wudu yesterday. Then I forgot whether I made wudu before praying asr or not. It was not today. It was yesterday. So do I have to repeat these prayers or not?
Answer
In the Name of Allah, the Most Merciful and Compassionate
In the situation explained above, you are required to repeat that prayer.
Leaving Doubts for Certainty
The reasoning behind this is a legal axiom: “Certainty is not removed by doubt.” In the scenario, you mentioned that you broke your wudu. In other words, you were certain that you did not have wudu. Thereafter, you prayed but you were unsure whether you made a new ablution beforehand. In other words, you have doubt whether you made a new ablution. [Ibn Nujaym, al-Ashbah wa al-Nazair]
In summary, you were certain that you did not have ablution and you doubted whether or not you made a new one. In this case, we leave the doubts and act according to certainty. This dictates, that you did not have ablution during the prayer and are then required to repeat it.
The Opposite Scenario
If we were to apply the above principle to the opposite scenario, it would look as follows: A person made wudu and prayed ‘Asr prayer. Later, a doubt arose in his mind whether he broke his wudu prior to praying ‘Asr. In short, he was certain that he had wudu and doubted whether he broke it. In this case, he considers his wudu intact and acts accordingly. He leaves the doubt and acts on certainty.
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani