Sunan an-Nasa'i, Volume 3, Book 23, Hadith 2587 (DarusSalam) ⓘ
It was narrated from 'A'idh bin 'Amr that: a man came to the prophet and asked him and he gave him, and when he placed his foot on the threshold the Messenger of Allah said: "If you knew how bad begging is, no one would go to anyone else and ask him for anything."
أَخْبَرَنَا مُحَمَّدُ بْنُ عُثْمَانَ بْنِ أَبِي صَفْوَانَ الثَّقَفِيُّ، قَالَ حَدَّثَنَا أُمَيَّةُ بْنُ خَالِدٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ بِسْطَامِ بْنِ مُسْلِمٍ، عَنْ عَبْدِ اللَّهِ بْنِ خَلِيفَةَ، عَنْ عَائِذِ بْنِ عَمْرٍو، أَنَّ رَجُلاً، أَتَى النَّبِيَّ صلى الله عليه وسلم فَسَأَلَهُ فَأَعْطَاهُ فَلَمَّا وَضَعَ رِجْلَهُ عَلَى أُسْكُفَّةِ الْبَابِ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لَوْ تَعْلَمُونَ مَا فِي الْمَسْأَلَةِ مَا مَشَى أَحَدٌ إِلَى أَحَدٍ يَسْأَلُهُ شَيْئًا " .
also referenced under: Hadith 2586 (Reference) & Book 23, Hadith 0 (In-Book)