Seven

THE SEVEN time-travel adventure series follows a group of kids who are given incredible powers (mapping to the gifts of the spirit) which begin day then find each other over the course of the book series. They unite to battle a villain who is trying to disrupt Bible history.
In the fifth book of the series GIANTS, Josh and the team travel back in time to the era of David to stop Dr. Bales who is working to change the outcome of David's fight against Goliath and possibly others!
THE SEVEN carefully follows biblical history and even throws in some archaeology to show the truth behind the Bible. Every book has a secret code adventurers can decipher, testing to see how carefully they are reading.