Mustadrak al-Hakim — Hadith 2420

It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said to me: "Do you know which will be the first group from my Ummah to enter Paradise?" I said: Allah and His Messenger know best. He (peace and blessings be upon him) said: "They will be the poor among the Muhajirun. They will come to the gate of Paradise on the Day of Resurrection and ask for it to be opened. The keepers of Paradise will say to them: Have you already been brought to account? They will say: For what should we be brought to account, when our swords were upon our shoulders in the path of Allah until we died in that state?" He (peace and blessings be upon him) said: "So it will be opened for them, and they will take their midday rest (qaylulah) there for forty years before the rest of the people enter."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.