"For to lie and deceive is in itself a great sin, but is greatly aggravated when we attempt to justify it, and seek to confirm it by invoking the name of God and using it as a cloak for shame, so that from a single lie a double lie, nay, manifold lies, result." Pr. Goodman discusses what that means in our lives.
Pastor Harrison Goodman moves into the 4th paragraph on the first commandment in Luther's Large Catechism. He teaches us how we end up making ourselves our own God and trust in ourselves more than we trust in the one, true God.