Hadith: First one to knock door of heaven.
It was narrated by imam Moslem in “Saheeh” (#196) from Anas ibn Malik: “I am the prophet with most followers in the doomsday, and first one who would knock the door of heaven”.
Shortest chain of this hadith is in “Mosannaf” by ibn Abi Shaiba (#35848):
حدثنا معاوية بن هشام حدثنا سفيان عن المختار عن أنس قال قال رسول الله صلى الله عليه و سلم أنا أول من يقرع باب الجنة
And it was also narrated by imam Tabarani from his way in “al-Awail” (#5, muasasat risala, darul furqan, Beirut):