The Prophet ﷺ used to perform ablution before every prayer, whether he was already in a state of purity or not.The narrator said, I asked Anas, "What did the rest of you do?"He replied, "We would perform a single ablution and pray with it."
حدثنا محمد بن حميد الرازي حدثنا سلمة بن الفضل عن محمد بن إسحق عن حميد
أن النبي ﷺ كان يتوضأ لكل صلاة طاهرا أو غير طاهر قال قلت لأنس فكيف كنتم تصنعون أنتم قال كنا نتوضأ وضوءا واحدا
No references are available.
[Its chain of transmission is daif] due to several defects, including the use of "an" (indicating a possible break in transmission) by Humayd and Ibn Ishaq, and the weakness of Muhammad bin Humayd. The following hadith, no. 60, serves in its place.