What is the ruling on intercourse during the daytime in Ramadan without ejaculation, for someone ignorant of the ruling?

The scholars have unanimously agreed that sexual intercourse during the daytime in Ramadan necessitates expiation (kaffarah), regardless of whether ejaculation occurred or not. This is based on the hadith of Abu Hurairah, agreed upon [by Al-Bukhari and Muslim], in which the Prophet, peace and blessings be upon him, did not inquire from the man who had intercourse with his wife about ejaculation. Therefore, whoever commits this act must repent and promptly offer the expiation.