Mutual aid is all about helping neighbors unconditionally. Groups often form around the core concept of mutual aid to help each other and their community, whether that be giving out food, teaching a skill, helping during a disaster, providing child care, giving computer or other technical assistance, acting as a translator, helping with filling out government forms, tutoring, and so much more. This help is given freely and with no strings attached. The expectation is that over time every member of the group or community will have opportunity to provide aid to others as well.
Mutual aid is fundamentally different than charity. Charity tends to create an us-and-them dynamic where the charitable organization is a hierarchical structure of power with the "victims" at the bottom being viewed, consciously or not, as less than the rest. Additionally, the charity given is often conditional. Mutual aid is not conditional.
These following quotes from cunyurbanfoodpolicy.org summarize it better than we could:
"mutual aid organizers are attuned to the needs of the collective over any other stakeholder, and the lines between those offering and receiving assistance are blurred"
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"Many contemporary charities have eligibility requirements for those receiving services based on sobriety, religious affiliation, income level, citizenship status, and more that arbitrarily assign deservingness to certain people and actively deny that food and shelter are essential human rights."