It is narrated from Sayyiduna Zayd bin Khalid al-Juhani, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "Whoever provides iftar to a fasting person will receive a reward equal to that of the fasting person, and the reward of the fasting person will not be diminished in the least."
In this hadith, the virtue and reward of providing iftar (breaking the fast) to someone is mentioned. This is the system of mercy in Islam: if a person fasts, he receives his reward; if he provides iftar, he receives a separate reward; and there is no reduction in anyone’s deeds.
In a narration of Bayhaqi, it is mentioned that we said, “O Messenger of Allah (sallallahu alayhi wa sallam)! Not everyone has the means to provide iftar to a fasting person.”
He (sallallahu alayhi wa sallam) replied: “This reward will also be given to the one who opens the fast of a fasting person with a sip of milk, or with a single date, or with a sip of water. And whoever feeds a fasting person to his fill, Allah, the Exalted, will make him drink a sip from my cistern (hawd), after which he will never feel thirsty until he enters Paradise.”