Is the following Hadith authentic?

Someone was arguing with me that going to the mesjid **isn't** obligatory. As evidence, he stated the following Hadith (he said it was in Saheeh Bukhari and Saheeh Muslim): > Some Sahaba (may Allah be pleased with them) were sitting with the Prophet (may the blessings and peace of Allah be upon him), they asked him to tell them who's one of the People of Jannah, and he (may the blessings and peace of Allah be upon him) said the first person to enter the door, then a Bedouin entered. After that, one (or more, I forgot) of the companions watched that Bedouin for 3 days, **and he/they saw that he prayed (the fardh) at home,** and he did no extra deeds, such as Tahajjud and voluntary fasting. Note I wrote the Hadith from memory when I heard him say it, I didn't take it from a Hadith book, there might be minor errors but I remember the important points. May Allah give us a better understanding of the religion, this is the first time I ever heard of such a Hadith! He even said that the Hadith was in Al-Nawawi's (may Allah have mercy on him) Riyadh As-Saliheen. Is it true that this Hadith is in Saheeh Bukhari, Saheeh Muslim, and even in Riyadh As-Saliheen? Jazakum Allah khayran,