Al-Matalib al-'Aliyah 3545 — Surah al-Baqarah

It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that in the blessed time of the Messenger of Allah (peace and blessings be upon him) a man had relations with his wife from behind (in the place of tillage, that is, the place of childbirth), and the people began to talk, saying: "So-and-so has done this with his wife from behind." Then Allah, the Mighty and Majestic, revealed this blessed verse: Your wives are a tilth for you, so come to your tilth however you wish [Surah al-Baqarah: 223], that is: "Your wives are like a field for you, so approach your field from whichever direction you wish (provided that it is the place of childbirth)."
The chain of this hadith contains Hisham bin Sa'd, who is saduq (truthful) but there is some criticism of his memory; however, it has supporting reports in the two Sahihs (Bukhari and Muslim) which strengthen its basic meaning.