Jeremiah 12:2b says: "You are near in their mouth and far from their heart."
This was me prior to a relationship with Jesus Christ. I could certainly talk a good game. If anyone asked if I was a christian, I would have said "yes". I could recite the books of the Bible in order, I could say the Lord's prayer, I knew all the "don'ts" in the Bible (i.e., DON'T: have sex, get drunk, lie, steal, covet, murder, etc), I knew John 3:16 by heart. Yep! I could talk a good game. Jesus was near in my mouth but very far from my heart. The next scripture in this chapter (verse 3) says, "BUT, You O Lord, know me; you see me and test my heart toward you". It says that He (God) knows me....not that He "knew" me. This speaks volumes to me. This means that at times I am still this person that can have Him "near in mouth, but far from heart". This tells me that I have to actively seek and work with the strength that He gives me to not be this person. I am capable of talking a good game but their are no games with God. He means what he says and says what He means. The fact that He "knows" me also tells me that although He has seen my sin nature, He didn't give up on me! Thank you Lord for Your love, your grace, and your mercy toward me!