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 is His Slave and Messenger.
It is permissible for someone who is obligated to pay Zakah to entrust another person to pay Zakah from his own money [i.e. from the money of this entrusted person], and it is not a condition that the entrusted person pays the Zakah from the very money of the person who entrusted him; rather, it is permissible for the entrusted person to pay the Zakah from his own money and then take the money from the person who is obligated to pay the Zakah; whether they are both in the same country or in different countries.
Al-Mardaawi said in Al-Insaaf: “If someone says to another, 'Pay the Zakah due on me from your money,' and he did so, then this is sufficient for the one who requested him to do so. This was explicitly stated (by Imaam Ahmad) as regards expiation. A group of scholars, including the author (Ibn Qudaamah), asserted the same for Zakah. In addition, the author of Ar-Ri’aayah said after quoting this: 'The scholars of the Hanbali School gave the Zakah the same ruling in this.'” [End of quote]
Imaam An-Nawawi said in Al-Majmoo’ regarding entrusting another person to pay Zakah (on one’s behalf): “The scholars of our School (the Shaafi’i School) said: whether he entrusted him to pay the Zakah from the money of the person who entrusted him or from the money of the entrusted person, both are permissible without any difference of opinion.”
Allaah Knows best.