The talk of the godly man is always wise may be rendered “When devout people talk, what they say always makes sense” (Good News Translation), or more simply “People who obey the Lord always talk wisely.”

But the fool changes like the moon: The moon is used as a symbol for being changeful and unstable, since it changes its appearance from night to night. In this context it is applied to the content of what foolish people say. What they say is unstable and always changing. Alternative models for this line are “but foolish people are always contradicting themselves” (Good News Translation), “but you never can tell what a fool will say next” (Contemporary English Version), and even “but a stupid person says one thing now and something else later.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Sirach. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here.