Psalm 141:3-4 (NIV)
Set a guard over my mouth, O Lord; keep watch over the door of my lips. Let not my heart be drawn to what is evil, to take part in wicked deeds with men who are evildoers; let me not eat of their delicacies.
Jesus said it is not what goes into a mouth that defiles a person but what comes out. The book of James chapter three says that the man who can control his tongue is a perfect man able to control his whole body. I remember an illustration given to children in Sunday school. The teacher brought a tube of toothpaste to class. He asked the kids to squeeze some out onto their hands. After several of the boys gleefully carried out his instruction, the teacher told them to put the toothpaste back in the tube. Of course, they made a worse mess trying but failing.
We do that with our words. Once they spill out it is nearly impossible to undo the damage. I am praying this prayer of the psalmist now. How easy is to get caught up is all the offerings of the world! I pray that all my conversation be pleasing to the Lord.