Giving Iftar to a fasting Person is an act of great merit. Zaib ibn Khalik Jehmi (Radhi Allahu Anhu) has related that our Prophet (Sallallahu Alai Wasallam) has said:-
من فطر صائما کان لہ مثل اجرہ عیر انہ لاینقص من اجر الصائم شیئ
“He who gives iftar to another fasting person shall earn reward equivalent to a fasting Person without detracting from the reward of the latter”. (Nisai and Tirmidhi)
Salman Farsi (Radhi Allahu Anhu) has related that our eternally blessed Prophet (Sallallahu Alai Wasallam) has said that, “If one breaks the fast of another, this act shall be a source of a pardon of his sins and release of his neck from hellfire, and he shall earn the merit of the fast of the fasting man, but the reward of the fasting man shall not be reduced”. The companion, upon hearing this submitted:
“Some of us do not have enough to break the fast of another”. Thereupon our Prophet (Sallallahu Alai Wasallam) give this reward even to those who give a date or water or a mouthful of milk to a fasting person”. (Sahih ibn Hazimah).