The Messenger of Allah ﷺ came out from the privy and was presented to him. They (the people) asked: Should we bring you water for ablution? He replied: I have been commanded to perform ablution when I get up for prayer. (Using translation from Abū Dāʾūd 3760)
أَنَّ رَسُولَ اللهِ ﷺ خَرَجَ مِنَ الْخَلَاءِ فَقُرِّبَ إِلَيْهِ طَعَامٌ فَقَالُوا أَلَا نَأْتِيكَ بِوَضُوءٍ قَالَ «إِنَّمَا أُمِرْتُ بِالْوُضُوءِ إِذَا قُمْتُ إِلَى الصَّلَاةِ»