Who originally said the phrase -An attack against one is an all?

The phrase "An attack against one is an attack against all" was originally said by the Three Musketeers, in the 1844 novel of the same name by Alexandre Dumas. The phrase is used as a rallying cry by the musketeers, who are bound together by a strong sense of loyalty and friendship. In the novel, the phrase is used to express the idea that an attack on any one of the musketeers will be met with a response from all of them. The phrase has since been used more generally to express the idea that an attack on one person or group is an attack on all people or groups who are similar to them.