Sahih Muslim
The Book of Commentary (Kitab Al-Tafsir)
Book Number: 041 / Hadith Number: 7162
'A'isha reported in connection with the words of Allah, the Exalted:" He who is rich should abstain, and he who is poor may reasonably eat (out of it)" that this was revealed in relation to the guardian of an orphan who is poor; he may get out of that what is reasonable keeping in view his own status of solvency.