It’s not uncommon to hear handouts being given on a “first come, first served” basis – or is it “first come, first serve”?
The answer is not necessarily as clear cut as one might hope. Part of this is due to the tendency to for speakers of any language to shortened and condense words. When analyzing the structure of the expression “first come, first served”, what is really being said is “whoever is first to come is the first to be served”. By looking at it in this way, it becomes clear that “served” is more grammatically correct than “serve”. This is an example of where ‘lazy language’ habits tend to drop “-ed” endings and other syllables in English expressions and idioms. By maintaining the “-ed” ending, the parallelism of the expression is also retained. This is another piece of evidence for why the word “served” should be used in this expression rather than “serve”.
Another interesting tidbit about the expression “first come, first served” is it’s also a service policy used by clients serving their customers. Abbreviated as FCFS and spelled out as “first-come, first-served”, this policy accepts customer requests to provide their orders as they arrive and without any other biases or preferences. This is also known as “first-in, first-served” and “first-come, first-choice”. This policy is also used widely in Western society as a standard method of seating people or serving queues. The name of this policy gives further support to the use of “served” in the expression.