It was narrated that Ibn 'Umar said:
"I heard the Messenger of Allah (ﷺ) say on the Minbar: 'Do not let the Bedouin make you change the name of your prayer; verily, it is 'Isha'.'" (RU)
English reference (RU): Vol. 1, Book 6, Hadith 543 (RU)
Arabic reference (RU): Book 6, Hadith 547 (RU)