As Salam alekum sheik, I had a sexual intercourse with my wife and next day my mother died so i buried her along with my cousin after Isha Prayer. But i heard that Prophet SAW has prohibited to enter in grave if one had sexual intercourse with there wife. Please explain in brief. also let me know the repent if i have committed a sin. Jazakallah

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

It might be that you are referring to the Hadeeth which was reported by Al-Bukhari  from Anas who said: “We were in the funeral procession of one of the daughters of the Prophet and he was sitting by the side of the grave. I saw his eyes shedding tears. He said, “Is there anyone amongst you who did not have sexual relations with his wife last night?” Abu Talhah replied in the affirmative. And so the Prophet told him to get down in her grave and he got down in her grave (and he buried her).”

It means that it is more appropriate for the person who undertakes the burial of the dead not to have had sexual intercourse with his wife, and the reason for this is that it is preferable that the burial of the dead be done by someone who is far from the enjoyment of this worldly life, as pointed by Ibn Hajar, may Allaah have mercy upon him, in "Fat'h Al-Baari".

In any case, a Muslim is not sinful for undertaking the burying after having had sexual intercourse with his wife. So, you should not worry about this matter.

Allaah Knows best.