Assalaamu alaykum wa rahmatullaahi wa barakaatuhu, Shaykh. I once combined the Thuhr and ‘Asr as my mother was sick and had fever and said that she wanted to go the hospital, so as per my knowledge and understanding, I combined the Thuhr and ‘Asr at the time for the Thuhr and then went to the hospital with her. I combined these prayers because I need to renew the ablution before every prayer due to my sickness as I did not know what the condition of the toilets at the health centre would be. Do I need to repeat that ‘Asr prayer or not? I had not taken any fatwa for it, but based on a fatwa that I was given regarding travelling from Makkah to Madeenah and other answers that I read on the internet, I took that decision and combined them. Please advice, Shaykh. May Allaah reward you.

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 is His slave and Messenger.

If the case is as you mentioned, that you have a sickness that requires that you perform ablution for every prayer, then combining the two prayers is permissible for you according to some scholars, such as the scholars of the Hanbali School of jurisprudence.

Kash-shaaf Al-Qinaa ‘an Matn Al-Iqnaa’ authored by Al-Buhooti from the Hanbali School, while elaborating on the cases of combining the prayers, reads:

"The sixth case is for a woman who has bleeding outside her monthly menses and the like, such as someone who has incontinence of urine or incontinence of Mathi (pre-seminal fluid) or nose bleeding and the like, as stated in the hadeeth of Hamnah when she asked the Prophet about bleeding outside her monthly menses and he said to her, 'If you are able to delay the Thuhr prayer and advance the 'Asr prayer, to perform Ghusl, and then combine the Thuhr and 'Asr; and then delay the Maghrib prayer and advance the 'Ishaa' prayer, to perform Ghusl, and then combine the two prayers, then do so.' [Ahmad, Abu Daawood and At-Tirmithi] A person who has incontinence of urine and the like is like her (i.e. his case is the same as the case of Hamnah).” 

Based on the above, you are not obliged to repeat the ‘Asr prayer, which you combined with the Thuhr prayer.

Please, refer to fataawa 85790 and 82828 for benefit on the permissibility of combining the prayer for a necessity provided that one does not make it a habit.

On the other hand, you should learn the rulings pertaining to the prayer and purity and other individual obligations. The Fatwa of Shaykh Ibn Taymiyyah, reads, “Seeking Islamic knowledge is a communal obligation with the exception of what is obligatory, such as every person seeking knowledge about what Allaah commanded him to do and what He forbade him from doing, as this is an individual obligation, as it was reported in Saheeh Al-Bukhari and Saheeh Muslim that the Prophet said, 'When Allaah wishes good for someone, He bestows understanding of the religion upon him.”

Allaah knows best.