The regular Imaam of the mosque was absent, so people asked me to lead the congregational prayer. I led the prayer and, while I was in the second Rak‘ah, I remembered that I had not performed ablution. I felt ashamed and embarrassed to leave the prayer, so I completed it. I do not know most of the people I led in prayer in order to apologize to them and inform them of the truth. I feel as if I had betrayed them and I do not know what to do. Can you advise me in this regard? May Allaah The Almighty Grant you guidance.

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

Completing the prayer while knowing your state of impurity was wrong and you should repent to Allaah The Almighty from such an act. You should have left the prayer after realizing your state of impurity and chose one of the worshippers to take your place and lead the congregational prayer. However, since you have already done so, you are not obliged to inform those whom you led and this does not constitute a betrayal to them since their prayer is valid as long as they did not know about your impurity.