[23a bottom] Shmuel’s father placed guards over captured women (who were brought to Nehardea to be ransomed) so that they would not be violated. Shmuel asked his father who was guarding the women until now, to which his father answered, “If they were your daughters, would you treat the matter so lightly?” Shmuel’s statement was like a “mistake that came from before the ruler,” (Rashi: like a royal decree made in error which is still irreversible). A man’s words may contain some prophecy of the future and therefore one should avoid mention of anything undesirable that could happen in the future [as we learn later that Shmuel’s own daughters indeed became captives (but thankfully were not violated and were even allowed to marry Kohanim)].
Prac-T-cal Tidbits: A person’s words are extremely powerful and we must always be extra careful to never open our mouths to misfortune (and never let the Satan/Angel of evil have an opportunity for destruction). Even accidental speech can carry heavy weight. If we try to only think and speak positively, we should merit to only have good come our ways, for ourselves, our families, our friends, and everyone around us.