Sahih Ibn Khuzaymah

It is narrated from Hazrat Muhammad bin Yahya (may Allah have mercy on him) that he said: I asked Ubaidullah bin Abdullah bin Umar, "In your opinion, is it narrated from anyone that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) used to perform ablution for every prayer, whether in a state of purity or impurity (with or without ablution)?" Ubaidullah replied that Asma bint Zaid bin Khattab narrated to him that Abdullah bin Hanzalah bin Abi Amir, who was washed by the angels (the narrator of the hadith is his son, not himself), narrated to her that the Messenger of Allah (peace and blessings be upon him) was commanded to perform ablution in every state, whether pure or impure. When this became difficult for the Messenger of Allah (peace and blessings be upon him), he was commanded to use the miswak at the time of every prayer, and the command of ablution for every prayer was lifted from him, except if his ablution was broken (then he would have to perform ablution again). Sayyiduna Abdullah (may Allah be pleased with him) thought that he had the strength to do this (to perform ablution for every prayer), so he continued to do so until his death. This is the narration of Yaqub bin Ibrahim. In the narration of Muhammad bin Mansur, these words are present: « وَكَانَ يَفعَلُهُ حَتَي مَاتَ » "He continued to act in this way until he passed away."