The Prophet sent (somebody) to his wives (to get something), but the messenger found nothing with them. Then Allah's Apostle said (to his companions). "Isn't there anybody who can entertain this man tonight so that Allah may be merciful to him?"
An Ansari man got up and said, "I (will entertain him), O Allah's Apostle!". So he went to his wife and said to her, "This is the guest of Allah's Apostle, so do not keep anything away from him." She said. "By Allah, I have nothing but the children's food." He said, "When the children ask for their dinner, put them to bed and put out the light; we shall not take our meals tonight." She did so.
In the morning the Ansari man went to Allah's Apostle who said, "Allah was pleased with (or He bestowed His Mercy on) so-and-so and his wife (because of their good deed)."
Then Allah revealed:
"But give them preference over themselves even though they were in need of that." (59.9)
- Sahih Bukhari