Why hast thou forsaken me?
Mark 15:34 And at the ninth hour Jesus cried with a loud voice, saying, Eloi, Eloi, lama sabachthani? which is, being interpreted, My God, my God, why hast thou forsaken me?
This will be the cry of those left behind, so let's examine why someone is left behind.
1. Because you have forsaken the Lord due to the wickedness of your doing.
Deuteronomy 28:20 The Lord shall send upon thee cursing, vexation, and rebuke, in all that thou settest thine hand unto for to do, until thou be destroyed, and until thou perish quickly; because of the wickedness of thy doings, whereby thou hast forsaken me.
2. Because you have not forsaken all to follow the Lord
Matthew 19:29 And every one that hath forsaken houses, or brethren, or sisters, or father, or mother, or wife, or children, or lands, for my name's sake, shall receive an hundredfold, and shall inherit everlasting life.
3. Because you forsook the Lord having loved the present world
2 Timothy 4:10 For Demas hath forsaken me, having loved this present world, and is departed unto Thessalonica; Crescens to Galatia, Titus unto Dalmatia.
4. Because you loved the wages of unrighteousness
2 Peter 2:15 Which have forsaken the right way, and are gone astray, following the way of Balaam the son of Bosor, who loved the wages of unrighteousness;
These are four possibilities, so examine yourself.