DD,

People who have encounters with Jesus can't keep quiet about it. Remember the Samaritan woman at the well? She couldn't keep quiet and when He returned, she brought the whole village with her. Remember the demoniac who was living in the cemetery and even breaking the chains people put on him to restrain him, and who was cleansed by Jesus? When Jesus returned, the man brought the entire village out to meet Him and hear His teaching. 

Yes, what God teaches us in scripture is the foundation for what we believe and teach, but it is our testimony that gets attention first and draws people into wanting to know more about God. Having a testimony is proof positive that a person has had an encounter with Jesus and the absence of one is proof they haven't. So when a person can't share even a tidbit of a testimony, that is clear evidence the power of God is not in them, not even if they are quoting scripture.