Musnad Ahmad Hadith 25115

Abu Khalaf says that he was present with Ubaid bin Umair in the service of Umm al-Mu'mineen Aisha (may Allah be pleased with her) and submitted, "At this time I have come to you to ask about a verse: how did the Prophet (ﷺ) recite it? Is it 'alladhīna ya'tūna mā ataw' or is it 'yu'tūna mā ataw'?" She asked, "Which of these two recitations do you prefer?" Ubaid replied, "By the One in Whose hand is my soul, one of these recitations is dearer to me than the whole world and whatever is in it." She asked, "Which one is that?" Ubaid replied, "'alladhīna ya'tūna mā ataw'." She said, "I bear witness that the Prophet (ﷺ) also recited this verse in this way, and in this way the verse was revealed. However, in spelling, both are the same letter (their root is the same)."