Zaid bin Khalid Al-Juhani (May Allah be pleased with him) reported:
The Allah's Messenger (peace and blessings of Allaah be upon him) said,
"He who provides a fasting person something with which to break his fast,
will earn the same reward as the one who was observing the fast,
without diminishing in any way the reward of the latter.'' [At-Tirmidhi].
