Today's Alleluia verse is John 14.6: "I am the way and the truth and the life. No one comes to the Father except through me." This is a huge claim ~ any nonbeliever must deal with it. Either Jesus spoke the truth or he's delusional. I personally found that all the rest about Jesus supports this claim ~ the pieces just fit together. And my own spiritual experience also bears witness to its truth.
In the Gospel from Mark 8, we learn that the Pharisees came to seek a sign from Jesus to test him ~ they did not see that the greatest sign from heaven was the Lord himself. It just shows that if you reject something that happens to be the truth, you remain blind. Accept it and you are illuminated.