Sunan Ibn Majah, Volume 5, Book 37, Hadith 4115 (DarusSalam) ⓘ
It was narrated from Mu’adh bin Jabal that the Messenger of Allah said: “Shall I not tell you about the kings of Paradise?’ I said: ‘Yes.’ He said: ‘A weak and oppressed man who wears tattered clothes and is not paid any heed. If he swears (an oath) by Allah, Allah fulfills it.’”
حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا سُوَيْدُ بْنُ عَبْدِ الْعَزِيزِ، عَنْ زَيْدِ بْنِ وَاقِدٍ، عَنْ بُسْرِ بْنِ عُبَيْدِ اللَّهِ، عَنْ أَبِي إِدْرِيسَ الْخَوْلاَنِيِّ، عَنْ مُعَاذِ بْنِ جَبَلٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " أَلاَ أُخْبِرُكَ عَنْ مُلُوكِ الْجَنَّةِ " . قُلْتُ بَلَى . قَالَ " رَجُلٌ ضَعِيفٌ مُسْتَضْعَفٌ ذُو طِمْرَيْنِ لاَ يُؤْبَهُ لَهُ لَوْ أَقْسَمَ عَلَى اللَّهِ لأَبَرَّهُ " .
also referenced under: Hadith 4115 (Reference) & Book 37, Hadith 4254 (In-Book)