Hadith #949 (Sunan al-Nasa'i)
Book: The Book of the Commencement of the Prayer
Narrator(s): Umarh bint 'Abdur Rahman عمرة بنت عبد الرحمن بن سعد بن زرارة, Umm Hisham bint Haritha bin al-Nu'man, Yahya bin Sa'id bin Farroukh al-Qatan يحيى بن سعيد بن فروخ القطان

He prayed Subh and recited Ar-Rum, but he stumbled in his recitation. When he had finished praying he said: ‘What is the matter with people who pray with us without purifying themselves properly? Those people make us stumble in reciting Quran.'”

Source: https://parallelquran.com/hadith/sunan-al-nasai-949/