It is narrated from Sayyiduna Abdullah bin Salam (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Between the two door-leaves of Paradise is a distance of forty years, and a day will surely come upon it when it will be crowded the way camels thirsty for five days crowd around water."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13984