Musnad Ahmad 28:95

Hassan narrated to us, Ibn Lahi'ah narrated to us, Abu 'Ashanah narrated to us, that he heard Abdullah ibn 'Amr saying: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Indeed, the first group to enter Paradise will be the poor of the Emigrants (Muhajirun), those through whom hardships are warded off. When they are commanded, they listen and obey. And if one of them has a need of the ruler, it is not fulfilled for him until he dies while it is still in his chest. And indeed, Allah, the Almighty and Majestic, will call Paradise on the Day of Resurrection, and it will come with its adornment and its decoration. Then He will say: 'Where are My servants who fought in My cause, were killed in My cause, were harmed in My cause, and struggled in My cause? Enter Paradise.' So they will enter it without reckoning and without punishment." And he mentioned the rest of the hadith.