"Narrated Abu Dhar: Allah's Apostle said, "While I was at Mecca the roof of my house was opened and Gabriel descended, opened my chest, and washed it with Zamzam water. Then he brought a golden tray full of wisdom and faith and having poured its contents into my chest, he closed it. Then he took my hand and ascended with me to the nearest heaven, when I reached the nearest heaven, Gabriel said to the gatekeeper of the heaven, 'Open (the gate).' The gatekeeper asked, 'Who is it?' Gabriel answered: 'Gabriel.' He asked, 'Is there anyone with you?' Gabriel replied, 'Yes, Muhammad is with me.' He asked, 'Has he been called?' Gabriel said, 'Yes.' So the gate was opened and we went over the nearest heaven and there we saw a man sitting with some people on his right and some on his left. When he looked towards his right, he laughed and when he looked toward his left he wept. Then he said, 'Welcome! O pious Prophet and pious son.' I asked Gabriel, 'Who is he?' He replied, 'He is Adam and the people on his right and left are the souls of his offspring. Those on his right are the people of Paradise and those on his left are the people of Hell and when he looks towards his right he laughs and when he looks towards his left he weeps.' Then he ascended with me till he reached the second heaven and he (Gabriel) said to its gatekeeper, 'Open (the gate).' The gatekeeper said to him the same as the gatekeeper of the first heaven had said and he opened the gate.
Anas said: "Abu Dhar added that the Prophet met Adam, Idris, Moses, Jesus and Abraham. He (Abu Dhar) did not mention on which heaven they were but he mentioned that he (the Prophet ) met Adam on the nearest heaven and Abraham on the sixth heaven." Anas said, "When Gabriel along with the Prophet passed by Idris, the latter said, 'Welcome! O pious Prophet and pious brother.' The Prophet asked, 'Who is he?' Gabriel replied, 'He is Idris." The Prophet added, "I passed by Moses and he said, 'Welcome! O pious Prophet and pious brother.' I asked Gabriel, 'Who is he?' Gabriel replied, 'He is Moses.' Then I passed by Jesus and he said, 'Welcome! O pious brother and pious Prophet.' I asked, 'Who is he?' Gabriel replied, 'He is Jesus. Then I passed by Abraham and he said, 'Welcome! O pious Prophet and pious son.' I asked Gabriel, 'Who is he?' Gabriel replied, 'He is Abraham. The Prophet added, 'Then Gabriel ascended with me to a place where I heard the creaking of the pens.' "
Ibn Hazm and Anas bin Malik said: The Prophet said, "Then Allah enjoined fifty prayers on my followers. When I returned with this order of Allah, I passed by Moses who asked me, 'What has Allah enjoined on your followers?' I replied, 'He has enjoined fifty prayers on them.' Moses said, 'Go back to your Lord (and appeal for reduction) for your followers will not be able to bear it.' (So I went back to Allah and requested for reduction) and He reduced it to half. When I passed by Moses again and informed him about it, he said, 'Go back to your Lord as your followers will not be able to bear it.' So I returned to Allah and requested for further reduction and half of it was reduced. I again passed by Moses and he said to me: 'Return to your Lord, for your followers will not be able to bear it. So I returned to Allah and He said, 'These are five prayers and they are all (equal to) fifty (in reward) for My Word does not change.' I returned to Moses and he told me to go back once again. I replied, 'Now I feel shy of asking my Lord again.' Then Gabriel took me till we reached Sidrat−il−Muntaha (Lote tree of the utmost boundary of the seventh heaven) which was shrouded in colors, indescribable. Then I was admitted into Paradise where I found small walls of pearls and its earth was of musk." "
- (Sahih Bukhari: book 8, hadith 345)