We all have family and friends who have failed to receive the Good News of the Gospel. The unsaved will be 'left behind' on earth to go through the "tribulation period" after the "Rapture". You remember how, for a short time, after (9/11/01) people were open to spiritual things and answers. (We are still singing "God Bless America" at baseballs' seventh inning stretch.) Imagine how taken back they will be by the millions of missing Christians and devastation at the rapture. They will know it was true and that they have blown it. There will be a small window of time where they might be reached for the Kingdom of God. We have made it possible for you to send them a letter of love and a plea to receive Christ one last time. You can also send information based on scripture as to what will happen next. Each fulfilled prophecy will cause your letter and plea to be remembered and a decision to be made.
"WHY" is one last chance to bring them to Christ and snatch them from the flames!