The economic boycott is one of the most powerful weapons of pressure. It is an effective weapon in confronting the Zionist enemy and its supporters, and it is one of the forms of insulting him and rejecting him that God Almighty has commanded His servants to do. ...One of the most obligatory duties for Muslims is to boycott this criminal entity, its companies, and the companies of its supporters, and to boycott them economically, and to prevent goods from reaching them, or to disrupt their arrival to them, or to target them by any means of jihad imposed specifically on every Muslim. Economic boycott is nothing but a type of jihad with money for the sake of God. ...
Naturally, the fatwa must find a precedent for boycotting Israel, and it finds one - from Mohammed himself!
The Prophet, may God’s prayers and peace be upon him, used the weapon of economic warfare against the Jews after they broke the covenant. After the incident of the Jew’s attack on the Muslim woman in the Bani Qaynuqa market and the killing of the companion, he boycotted them economically before besieging and expelling them.