Halakhah su Ecclesiaste 9:18

It is taught in a baraita (Eruvin 13a): Rabbi Meir said, when I came to Rabbi Ishmael, he said to me “My son, what is your trade?” I said to him “I am a scribe.” He said to me “My son, be meticulous in your work, for it is the work of heaven, and if you should omit a single letter or add a single letter, you destroy the entire world.” From this we may see that a scribe must be in extreme awe of God, for if he makes one error or fails to make one necessary correction, his soul will perish, because he steals from the masses and causes them to sin – they remain in a state of not performing commandments, and every day make blessings in vain. Of him it is written “One sinner destroys much good” (Kohelet 9:18), and “Cursed is he who does God’s work deceitfully” (Jeremiah 48:10). Therefore, those who have the power to appoint scribes should appoint worthy scribes, men of truth who hate bribes and know Torah, fear God and tremble at his words, just as we appoint kosher butchers. All who write tefillin as good and fit as they possibly can will have their reward doubled and doubled again, and will be saved from the judgement of Gehinnom. (From the laws of writing tefillin by R’ Avraham Mazinsheim and in the Levush.)