AHah's Messenger ﷺ was on his way back from 'Arafat and as he reached the creek (of a hillock) he got down and urinated (Usama did not say that he poured water), but said: He (the Holy Prophet) called for water and performed ablution, but it was not a thorough one. I said: Messenger of Allah, the prayer! Thereupon he said: Prayer awaits you ahead (at Muzdalifa). He then proceeded, until he reached Muzdalifa and observed sunset and 'Isha' prayers (together) there.  

سَمِعْتُ أُسَامَةَ بْنَ زَيْدٍ يَقُولُ أَفَاضَ رَسُولُ اللَّهِ ﷺ مِنْ عَرَفَاتٍ فَلَمَّا انْتَهَى إِلَى الشِّعْبِ نَزَلَ فَبَالَ وَلَمْ يَقُلْ أُسَامَةُ أَرَاقَ الْمَاءَ قَالَ فَدَعَا بِمَاءٍ فَتَوَضَّأَ وُضُوءًا لَيْسَ بِالْبَالِغِ قَالَ فَقُلْتُ يَا رَسُولَ اللَّهِ الصَّلاَةَ قَالَ الصَّلاَةُ أَمَامَكَ قَالَ ثُمَّ سَارَ حَتَّى بَلَغَ جَمْعًا فَصَلَّى الْمَغْرِبَ وَالْعِشَاءَ