Imam Ibn Qudaamah said, “Jihad is an obligation upon the community; if some people undertake it, the rest are relieved of the obligation.”
What fard kafaayah means is that if it is not undertaken by enough people, then all the people are guilty of sin, but if enough people undertakes it, the rest will be relieved of blame. Initially the command is addressed to all of them, as in the case of an individual obligation (fard ‘ayn), but then in the case of fard kafaayah the obligation is dropped if enough of the people undertake to do it, unlike the case with fard ‘ayn where the obligation is not dropped if someone else does it. Jihad is a fard kafaayah, according to the majority of scholars.”
Ref: Al-Mughni, 9/163
Shaykh Baz said, “We have previously explained on more than one occasion that jihad is fard kafaayah (communal obligation) , not fard ‘ayn (individual obligation).
All Muslims are enjoined to support their brothers with their selves (i.e., physically, by joining them), or with money, weapons, da’wah and advice. If enough of them go out (to fight), the rest are freed from sin, but if none of them do that then all of them are sinners. The Muslims in Saudi Arabia, Africa, North Africa and elsewhere are obliged to do their utmost, and if there is a jihad in one country, the surrounding countries should hasten to help them, the closest then the next closest.
If one or two states, or three or more, manage to fulfil the obligation, then the rest are freed of responsibility. They deserve to be supported, and it is obligatory to help them against their enemies, because they are oppressed.
Allaah has enjoined jihad upon all Muslims, and they must fight against the enemies of Allaah until their brothers are victorious. If they fail to do that then they are sinners, but if sufficient people undertake to do that, then the rest are absolved of sin.”
Ref: Fataawa al-Shaykh Ibn Baaz, 7/335
Posted by Abdul Kareem Ibn Ozzie