I know this - and I know that!
(J.C. Ryle)
"In the synagogue there was a man possessed by a demon, an evil spirit. He cried out at the top of his voice: Ha! What do you want with us, Jesus of Nazareth? I know who You are - the Holy One of God!" Luke 4:33-34
"Moreover, demons came out of many people, shouting: 'You are Christ the Son of God!' But He rebuked them and would not allow them to speak, because they knew that He was the Christ." Luke 4:41
We should notice, in this passage, the clear religious knowledge possessed by the devil and his agents. Twice in these verses we have proof of this. "I know who you are - the Holy One of God!" was the language of an an evil spirit in one case. "You are Christ the son of God," was the language of many demons in another. Yet this knowledge was a knowledge unaccompanied by faith, or hope, or charity. Those who possessed it were miserable evil beings - full of bitter hatred both against God and man.
Let us beware of an unsanctified knowledge of the truths of Christianity. It is a dangerous possession, but a fearfully common one in these latter days. We may know the Bible intellectually - and have no doubt about the truth of its contents. We may have our memories well stored with its leading texts, and be able to talk glibly about its leading doctrines. And all this time the Bible may have no influence over our hearts, and wills, and consciences. We may, in reality, be nothing better than the demons!
Let it never content us to know religion with our heads only. We may go on all our lives saying, "I know this - and I know that!" - and sink at last into Hell with the words upon our lips! Let us see that our knowledge bears fruit in our lives.
Does our knowledge of sin make us hate it?
Does our knowledge of Christ make us trust and love Him?
Does our knowledge of God's will make us strive to do it?
Does our knowledge of the fruits of the Spirit make us labor to show them in our daily behavior?
Knowledge of this practical kind is really profitable.
Any other religious knowledge will only add to our condemnation at the last day!