The Gates of Paradise
Paradise has gates through which the believers, like the angels, will enter:
"'Adn [Eden - everlasting gardens] of Paradise, whose doors will open for them" [38:50]
"...And angels shall enter unto them from every gate [with the salutation]: "Peace be unto you for that you persevered in patience! How excellent is the final home!" [13:23-24]
Allah (swt) has told us that these gates will be opened when the believers reach them, and they will be welcomed by the angels with greetings of peace:
"...til, when they reach it, its gates will be opened, and its keepers will say, "Salaamun 'alaykum! You have done well, so enter here to abide therein." [39:73]
The number of gates in Paradise is eight, one of which is called ar-Rayyaan, which is exclusively for those who fast.
al-Bukhaari and Muslim report from Sahl ibn Sa'eedi that the Messenger of Allah (saw) said,
"In Paradise there are eight gates, one of which is called ar-Rayyaan. No one will enter it except those who fast, and when they have entered it will be locked behind them and no one else will enter it". [Ibn Katheer, an-Nihaayah, 2/214]
In addition to ar-Rayyaan, there are also gates for those who pray much, those who give in charity and those who fight in jihaad; Abu Hurayrah (ra) reported that the Prophet (saw) said, "Whoever spends a pair [of anything] from his wealth for the sake of Allah (swt) will be called from the gates of Paradise, and Paradise has eight agates. Whoever used to pray [regularly and properly] will be called from the gate of prayer; whoever use to give in charity will be called from the gate of charity' whoever used to fight in jihaad will be called from the gate of jihaad, and whoever used to fast [regularly] will be called from the gate of fasting". Abu Bakr (ra) said, "By Allah, it would not matter if a person was called from any of them but will anyone be called from all of them, O Messenger of Allah (saw)?" He said, "Yes, and I hope that you will be one of them ". [saheeh, Ibn Katheer, an-Nihaayah, 2/214]
The Prophet (saw) also said, "Whoever performs wudhu and does it properly, then lifts his gaze to the sky and says, "Ashhadu an laa ilaaha illa Allah, wahdahu laa shareeka lah, wa ashhadu anna Muhammadan 'abdahu wa rasuluhu, the eight gates of Paradise will be opened to him, and he will enter it through whichever one he wishes". [Muslim, Ahmad and others on the authority of 'Umar, an-Nihaayah, 2/219]
The Prophet (saw) told us that there is a gate, which is only for those who will not be called to account: this is the right-hand gate of Paradise. Everyone else will enter Paradise with the rest of the nations through the other gates. In a hadith about ash-Shafaa'ah (intercession) whose authenticity is agreed upon, Abu Hurayrah reported that the Prophet (saw) said, "Allah (swt) will say, "O Muhammad, admit those of your ummah who do not need to be brought to account through the right-hand gate and the others will enter through the other gates like the rest of the people."
In the same hadith, the Prophet (saw) described the width of the gates of Paradise:
"By the One in Whose Hand is the soul of Muhammad, the distance between two panels of the gates of Paradise or between the two gateposts, is liek the distance between Makkaah and Hajar, or between Makkah and Basra" [an-Nihaayah, 2/221]
The Prophet (saw) has told us that the gates of Paradise are opened during Ramadhaan. al-Bukhaari, Muslim, and Ahmad report from Abu Hurayrah that the Messenger of Allah (saw) said, "When the month of Ramadhan comes, the gates of heaven are opened".
In some reports it states that the distance between the two gate-panels when they are open is that of a forty year journey.
The Messenger of Allah (saw) said, "The distance between the two gate-panels of one of the gates of Paradise is the distance of forty-year's walking, but there will come a time when it is very crowded". [Ahmad in al-Musnad, Abu Na'eem in al-Hilyah, from Haakim ibn Mu'aawiyah from Mu'aawiyah, sahih; see also Muslim and Ahmad on the authority of 'Utbah ibn Ghazwaan]
And in the narration of at-Tabaraani reported in al-Mu'jam al-Kabeer from 'Abdullaah ibn Salaam, it is said "..and it [the gate] will become as crowded as a drinking-trough surrounded by thirsty camels".