There are a variety of spiritual applications for this trick including:
Be Alert – Use 1 Peter 5:7 and explain that if a simple illusion can be this tricky, how much more alert do we need to be in everyday life.
God’s Love – No volunteer necessary. Just show the deck to be all the same card. This deck only shows one card. Did you know that God loves everyone in the world the same? He doesn’t love good people more or bad people less and there’s nothing you can say or do to change how God loves you. The Bible says that God loves the world. Have everyone repeat John 3:16 with you. But the world is made up a many different and unique people. Thumb the deck again to show that each card is different. Some have red hair. Some black. Tall people. Short people. Good people. Bad people. God sees each person as an individual. Remove a black and red card from the deck and explain that although we are all different, we all fit into one of two categories – Saved or Lost. Explain that the red card represents the blood of Jesus and how he gave His life for us, just like John 3:16 says. This card is red because this person has received Jesus as his Lord and Savior (John 1:12). Explain that the black card represents “sin.” Tell a story about a person who is lost (many times, I’ll explain that he is a good person but even good people need Jesus).
Other applications – Once you play around with this trick, you’ll see that there are a variety of ways to use this card deck and a variety of spiritual applications to teach God’s Truth as well.