Titus 1:16 They profess to know God, but by their deeds they deny Him, being detestable and disobedient and worthless for any good deed.
Many people claim to know God, including both those who profess to be Christians and those outside of the church, whose lifestyles demonstrate the opposite. What they claim is but a lie if the way they live invalidates their claims. There are many who profess to know God but deny Him by their works. There are many who claim to follow Christ, for example, and yet take pleasure in the very things that nailed Him to the cross! Though these people would never with words renounce Christ, they are nevertheless denying Him by the things they do. Even though they will say wonderful things about God and Christ, yet all the while they are detestable and disobedient and worthless for any good deed.
1 John 3:18 Little children, let us not love with word or with tongue, but in deed and truth.
The apostle John would have us validate our claims by our actions and lifestyles. Indeed, the Lord Jesus Himself declared: "If you love Me, you will keep My commandments" (John 14:15). Therefore, the question at the end of the day is not, "Do you know God?" or "Do you love Jesus?" but rather: "Are you obeying Him?"
Those whose lifestyles are not characterized by a serious (though not perfect, of course) commitment to obeying the Lord ought not call Him their Lord; they ought to drop the worthless claims and live how they will. It makes no sense to call Jesus Lord—which designates Him as the sole authority to govern every area of one's life—and then to refuse to serve Him as Lord. That is why He would say: "Why do you call Me, 'Lord, Lord,' and do not do what I say?" (Luke 6:46). Those who claim that they know and follow Christ while refusing to actually serve Him as Lord are hypocrites—they are for show only, and not the real deal; they are mere pretenders, not true disciples of Christ.
Revelation 3:15-16 I know your deeds, that you are neither cold nor hot; I wish that you were cold or hot. So because you are lukewarm, and neither hot nor cold, I will spit you out of My mouth.
If we are not interested in obeying Christ, then we should go out into the world and live like out and out pagans, and we ought not to lie by calling ourselves Christians. If it is the world we want, we ought to pursue it with all our heart! Be honest! Stop lying and remove the mask! If, however, we are going to say we follow Christ, then let us leave behind this fleeting world and follow Him with all our heart, soul, mind, and strength! God hates the double-minded man (Psalm 119:113; James 1:7-8). If you are double-minded, rest assured that God hates you! He is looking for those whose heart is completely His:
2 Chronicles 16:9 For the eyes of the LORD move to and fro throughout the earth that He may strongly support those whose heart is completely His.