Sahih Muslim Book 6, Hadith Number 2464.

Chapter : Sexual Intercourse is completely forbidden during the day in the month of Ramadhan.

‘Abbad b. Abdullah b. Zubair narrated that he heard ‘Aisha (Allah be pleased with her) saying: A person came to the Messenger of Allah (may peace be upon him), and he then narrated the Hadith. But (neither these words are found):”Give charity, give charity” (nor) his words: “during the day time”.