Tosefta su Ester 9:28

The reading of the megillah and the donation of shekels can be moved earlier but not moved later. Uncertain [date of] circumcision, the time of the donation of wood for the alter, the 9th of Av, the hagigah offering, and hakhel can be moved later but not earlier. Even though they said that megillah reading is moved earlier and not later, the megillah is read and [gifts for the needy] are collected and distributed on that day [the fourteenth] because the poor are look forward to the scheduled day of megillah reading, as it says (Esther 9:28) "These days will be remembered and practiced..." to fulfill the happiness in the appropriate time.