Sanhedrin 42 - Once A Verdict Has Been Reached
Once a verdict has been reached and the defendant is pronounced guilty, they take him out to stone him. The stoning place was located outside the courthouse. A court that sentences even one person in seven years is called "destroyer," and it would have been aggravated if the execution happened nearby.
While the condemned is being escorted to the execution grounds, one man stands at the courthouse door with a flag in his hand, and another sits astride a horse at a distance. If someone says, "I have grounds to argue for his acquittal," the flagman waves the flags and the horse with its rider races to the execution party and halts it. Even if the condemned himself says, "I have grounds for my own acquittal," they return him to the courthouse to hear his arguments, even four or five times, as long as there is substance to his words.
Art: Edouard Manet - Rue Mosnier with Flags