When you say less, you can avoid getting into trouble. The proverb is a reminder to be careful about what you say and to think before you speak. It suggests that it is better to err on the side of caution and remain quiet than to talk too much and risk getting into trouble.
The origin of the proverb “A close mouth catches no flies” is unclear, but it is believed to have originated in the 1600s. The phrase was first recorded in Thomas Fuller’s 1659 work “The Appeal of Injured Innocence”, and it is found in a number of languages, including Spanish, French, and Dutch.