In his book, The Enormous Exception, Earl Palmer tells about a pre-med undergrad at the University of California Berkley who became a Christian after a long journey through doubts and questions. 

As a student he had been hit with a bout of the flu that kept him out of school for 10 days. During that critical absence from his organic chemistry class, a classmate who happened to be a Christian carefully collected all his missed lectures and assignments. Then the Christian friend took time from his own studies to help his friend catch up to the rest of the class.

Years later, the pre-med student, now a committed Christian, told Palmer, "You know that this just isn't done, and I probably wouldn't have done it, but he gave that help to me without any fanfare or complaints. I wanted to know what made this friend of mine act the way he did; I found myself asking him if I could go to church with him."

Palmer wrote, "I think the best tribute I ever heard concerning a Christian was the tribute spoken of this student. 'I felt more alive when I was around this friend.'"

Actions speak louder than words.  

"By this everyone will know that you are my disciples, if you love one another." John 13:35