Everybody know that Peter denies Jesus three times before the crock crows. Peter denies Jesus with his words, but unlike Peter, we moderns deny Jesus with our actions. Unlike Peter, we would never deny Jesus with our words, because we have no Roman soldiers to fear. This is not first century Palenstine, this is the United States of America, the most popular place on the planet to say, "Jesus."
We moderns specialize in confessing to know Jesus because it's popular to know him, to sing praise songs about him, to wear JESUS tee-shirts, and large crosses around our necks. Yes, it's good to profess to know Jesus, but Titus reminds us that our profession without our works denies that what we say is true. If we profess to know Jesus, and do what those who do not profess to know him do, then in the words of Titus: "We deny we know him."
Not unlike Peter, we love Jesus, even though we deny him. But like Peter, we must confess our sin of denial, and begin again to walk with him.