Hidalgo rang the church bell to gather his congregation, then called for Mexican independence, the exile or arrest of all Spaniards in Mexico, and ended by calling out, "Mexicanos, viva México!" (Mexicans, long live Mexico!)
Mexico achieved independence in 1821, and since then the President of Mexico traditionally rings Hidalgo's bell (now at the National Palace on the Zocalo in Mexico City) and repeats Hidalgo's words each year at midnight as the 15th of September becomes the 16th of September.
See also: Fiestas Patrias