Embedded in its discussion concerning the dangers of holding onto already paid-up notes of indebtedness, today’s daf (Ketubot 19b) quotes a teaching of Rabbi Ami that it is permitted to be in possession of a ספר (which is understood to directly refer to a Sefer Torah or any volume of Tanach, and which the later commentaries extend to Gemarot and other halachic works) containing scribal/printing errors for up to thirty days, but from then on, it is prohibited to keep it.
In terms of the reasoning of this law which was later codified by the Rambam (Hilchot Sefer Torah 7:12) and Shulchan Aruch (Yoreh Deah 279:1), it is to prevent errors creeping into the authoritative Torah texts and to prevent mistakes in halachic decision-making where a decisor has relied upon a faulty text.
However, beyond the literal application of this law, various commentaries explain that the ultimate ספר (book) is the book of our life (as captured by the words זה ספר תולדות האדם – ‘This is the book of the chronicles of mankind’ – Bereishit 5:1). And it is on this basis that Rabbi Shlomo HaKohen M’Radomsk (as quoted by Rabbi Aharon Perlov in his ‘Margaliot HaShass’) explains that just as we must check physical books for writing/printing errors that may have accidentally crept into them and which may lead to further errors if not fixed, we must also check ourselves for spiritual/practical errors that may have crept into our spiritual mindset and which may lead to further errors if not fixed.
Of course, most of us agree with the principle of conducting a spiritual audit to identify and fix our errors, and we generally do so annually as part of our divine service approaching Rosh Hashanah and Yom Kippur. But it is precisely because this is such an infrequent activity that Rabbi Shlomo HaKohen’s explanation of our daf is so important – because what he is saying to us is that just as a sefer containing textual errors that are not addressed for over 30 days can contribute to further errors, so too, a person who has erred in how they perceive Judaism and spirituality and who does not address these mistakes within a 30 day period can find that they can directly contribute to further errors in terms of specific religious attitudes and practices.
Ultimately, if we need to worry about scribal/printing errors in books, we should also worry about personal/spiritual errors in ourselves, and in both cases we should do what we can to address and fix them asap.