Halakhah к Мишлей 10:7

“But the name of the wicked shall rot” (Prov. 10:7). This refers to scribes who add words, delete or lose words, also those who seek to allude to their names by means of acrostics. Moreover, because of their repulsive name should they then deliberately omit, add or exchange words? Concerning them it is said, “Thou hast blotted out their name for ever and ever” (Ps. 9:6).

17. It is a custom of all Jews that the reader reads and spreads out [the Megillah] like a letter in order to make the miracle seen. And when one finishes, one goes back and wraps it all up and makes a blessing. RAMA: There is what is written that we say four verses of redemption in a loud voice, [the verses are] "A Jewish Man", "And Mordechai went out", "The Jews had light", "Because Mordechai the Jew" and such is the custom in our lands. [Hagahos Maimoni; Kol Bo; Avudraham]. And then the reader goes back and reads these verses. It is also written that the young children are accustomed to draw pictures of Haman on trees or stones or to write the name of Haman on themselves and to strike one against the other in order to blot out his name according to "The name of Amalek shall surely be erased" (Devarim 25:19) and "But the fame of the wicked rots". (Proverbs 10:7). From this is derived the custom that we strike Haman wen we read the Megillah in the synagogue [Avudraham]. We must not nullify any custom nor should we ridicule [any custom] because "לא לחנם הוקבע". [Beis Yosef]