Hadith 1758 - Bab 343 (Prohibition of passing in front of a Worshipper while he is offering Salat (Prayer))
Chapter 18 (The Book of the Prohibited actions)

Abul-Juhaim 'Abdullah bin Al-Harith (May Allah be pleased with him) said: The Messenger of Allah (Peace be upon him) said, "If the person who passes in front of a praying person, realizes the enormity of the sinfulness of this act, it will have been better for him to wait forty than to pass in front of him."

[Al-Bukhari and Muslim].

[The narrator was not sure whether the Prophet (Peace be upon him) said forty days, months or years.]

Abdullàh Ibn Al-Hâreth Ibn As-Samma Al-Ansàri (das) rapporte: «Le Messager de Dieu (bsdl) a dit: Si celui qui passe devant l"orant (quelqu"un qui prie) savait ce qu"il encourait, il aurait attendu quarante, avant de passer devant lui. (Le Rapporteur ne sait pas s"il s"agit de 40 jours ou 40 mois ou 40 années). (ura)