Majma al-Zawaid — Hadith 17897

Abd al-Rahman bin Sabit narrates: Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) sent a message to Sayyiduna Sa'id bin Amir (may Allah be pleased with him): I am appointing you as the commander over these people; take them to the land of the enemy and wage jihad along with them! The narrator says: Then he mentioned a long hadith, in which, further on, are these words: Sayyiduna Sa'id bin Amir (may Allah be pleased with him) said: I will not stay behind from any first expedition, after I heard the Prophet (peace and blessings be upon him) say: "Indeed, the poor Muslims will proceed in a flock just as pigeons proceed in a flock." The Prophet (peace and blessings be upon him) said: "It will be said to them: Halt for the reckoning! They will say: By Allah! We did not leave behind anything for which we should be called to account. Allah Almighty will say: My servants have spoken the truth." The Prophet (peace and blessings be upon him) said: "So they will enter Paradise seventy years before other people."
Imam al-Tabarani recorded it.