God’s love is for everyone . . . it’s not secret.
Who likes a good mystery? That's what we're going to talk about. But first, we're going to solve one:
Have a 25 or 50 piece puzzle dumped on the floor before everyone arrives. Hide between 1 and 3 pieces around the room (remember where you put them), but don't tell your students about the missing pieces until someone says, "Hey! There are pieces missing!" Then, for fun, have them bunch up as a group (or in groups) and find the missing pieces playing "Hot or Cold".
(Hot or Cold: the closer they are to the missing piece's location the “hotter” they are. Depending on their location in the room, you call out, Freezing…cold…lukewarm…warm…warmer…hot…burnin’ up!” until they’ve found all the missing pieces.)
After they've put the puzzle together w/the missing pieces, have them get in a group (or small groups) for the discussion.
Read the Following Passage from the Bible:
Ephesians 3:4-11 NLT
As you read what I have written, you will understand what I know about this plan regarding Christ.  God did not reveal it to previous generations, but now he has revealed it by the Holy Spirit to his holy apostles and prophets.  And this is the secret plan: The Gentiles have an equal share with the Jews in all the riches inherited by God's children. Both groups have believed the Good News, and both are part of the same body and enjoy together the promise of blessings through Christ Jesus.  By God's special favor and mighty power, I have been given the wonderful privilege of serving him by spreading this Good News.  Just think! Though I did nothing to deserve it, and though I am the least deserving Christian there is, I was chosen for this special joy of telling the Gentiles about the endless treasures available to them in Christ.  I was chosen to explain to everyone this plan that God, the Creator of all things, had kept secret from the beginning.  God's purpose was to show his wisdom in all its rich variety to all the rulers and authorities in the heavenly realms. They will see this when Jews and Gentiles are joined together in his church.  This was his plan from all eternity, and it has now been carried out through Christ Jesus our Lord.