What is forbidden in the fourth commandment?

The fourth commandment forbiddeth the omission or careless performance of the duties required (Ezekiel 22:26; Amos 8:5; Malachi 1:13), and the profaning the day by idleness (Acts 20:7,9), or doing that which is in itself sinful (Ezekiel 23:38), or by unnecessary thoughts, words, or works, about worldly employments or recreations (Jeremiah 17:24-27; Isaiah 58:13).