"Christians must live in such a manner that their lives would make no sense if their God does not exist."
Christianity is more than a religious hobby that offers us a convenient sin-management program with a nice afterlife thrown in as a bonus.
It's a life where Jesus Christ, risen from the dead, is the center of all our loves, all our affections. And as that gets worked out in the stuff of life, the Christian life begins to look increasingly and significantly different from the average.
"He who was seated on the throne said, 'Behold, I am making all things new.'” ~ Revelation 21
"If anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come." ~ 2 Corinthians 5
Jesus didn't just come to make us nice. Your grandmother can make you nice
Jesus came to make us new.