Is it obligatory to respond to a gift or favour in kind or is it sufficient to just say "Jazaaka Allaah Khayran", even if one is able to respond in kind.
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is recommended but not obligatory for someone who receives a favor or is given a gift to return the favor. The Prophet, sallallaahu ‘alayhi wa sallam, said: “If someone does you a favor, then do something in return, and if you cannot find the means of doing so, then keep supplicating for him until you think that you have returned the favor.” [Ahmad]
Kash-shaaf al-Qinaa‘ reads: “It is prescribed for one who receives a gift to return the favor to the giver; if one cannot do so, he should mention it and commend the giver, and he should say "Jazaakallaahu khayran."” [End of quote]
Also, Mataalib Uli An-Nuha reads (section on Gifts): “The receiver of the gift should return the favor or pray for him; (it is recommended to do so) regardless of whether or not the favor is returned.” [End of quote]
Based on the above, you are not required to compensate someone who gave you a gift or did you a favor, even if you are able to return the favor; it is only desirable for you to do so.
Allaah Knows best.
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