Satan is the “father of lies,” and this why those under his sway speak lies and murder with their words and deeds (Jn. 8:44). This is also why Christians are frequently attacked here by the Devil, just like the woman in the Garden in the beginning. The fundamental lie is about the goodness of God and His Word. But if we repudiate that lie, we will hate all other lies and love the truth. 

The Text: “Wherefore putting away lying, speak every man truth with his neighbor: for we are members of one another” (Eph. 4:25). 

WSC Q. 77 What is required in the Ninth Commandment? The ninth commandment requireth the maintaining and promoting of truth between man and man, and of our own and our neighbors’ good name, especially in witness-bearing.

WSC Q. 78 What is forbidden in the ninth commandment? The ninth commandment forbiddeth whatsoever is prejudicial to truth, or injurious to our own or our neighbor’s good name. 

Heidelberg. Q 112 What is required in the ninth commandment? That I do not bear false witness against anyone, twist anyone’s words, be a gossip or a slanderer, or condemn anyone lightly without a hearing. Rather I am required to avoid, under penalty of God’s wrath, all lying and deceit as the works of the devil himself. In judicial and all other matters I am to love the truth, and to speak and confess it honestly. Indeed, insofar as I am able, I am to defend and promote my neighbor’s good name.