Sayyiduna Abdullah bin Salam (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "Between the two leaves of a door of Paradise is a distance of forty years' travel, and a day will come when it will be thronged as camels throng that are thirsty and come (to drink water) on the fifth day."
Al-Tabarani recorded it; its chain contains Ruzayk bin Abi Ruzayk, whom I do not know, and the rest of its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب أهل الجنة / 18646