The Messenger of Allah ﷺ drank some milk and he did not rinse his mouth nor did he perform ablution, and he offered the prayer.
أَنَّهُ سَمِعَ أَنَسَ بْنَ مَالِكٍ يَقُولُ إِنَّ رَسُولَ اللَّهِ ﷺ شَرِبَ لَبَنًا فَلَمْ يُمَضْمِضْ وَلَمْ يَتَوَضَّأْ وَصَلَّى قَالَ زَيْدٌ دَلَّنِي شُعْبَةُ عَلَى هَذَا الشَّيْخِ
[Machine] He heard Anas ibn Malik say: "The Messenger of Allah ﷺ drank milk, yet he did not rinse his mouth or perform ablution, and then he prayed." Zaid said: "Shu'bah informed me of this sheikh and we were narrated from Ikrimah who narrated from Ibn Abbas that he said: 'If it were not for the inconvenience, I would not have refrained from rinsing my mouth.'"
أَنَّهُ سَمِعَ أَنَسَ بْنَ مَالِكٍ يَقُولُ إِنَّ رَسُولَ اللهِ ﷺ شَرِبَ لَبَنًا فَلَمْ يُمَضْمِضْ وَلَمْ يَتَوَضَّأْ وَصَلَّى قَالَ زَيْدٌ دَلَّنِي شُعْبَةُ عَلَى هَذَا الشَّيْخِ وَرُوِّينَا عَنْ عِكْرِمَةَ عَنِ ابْنِ عَبَّاسٍ أَنَّهُ قَالَ لَوْلَا التَّلَمُّظُ مَا بَالَيْتُ أَنْ لَا أُمَضْمِضَ