Why have you forsaken me?
Matthew 27:46 And about the ninth hour Jesus cried with a loud voice, saying, Eli, Eli, lama sabachthani? that is to say, My God, my God, why hast thou forsaken me?
I believe this is what the rapture will be. When some saints are raptured for those left behind the cry will be "why hast thou forsaken me"?
47 Some of them that stood there, when they heard that, said, This man calleth for Elias. 48 And straightway one of them ran, and took a spunge, and filled it with vinegar, and put it on a reed, and gave him to drink. 49 The rest said, Let be, let us see whether Elias will come to save him. 50 Jesus, when he had cried again with a loud voice, yielded up the ghost.
To me this is a preview of the restrainer stepping aside.
51 And, behold, the veil of the temple was rent in twain from the top to the bottom; and the earth did quake, and the rocks rent; 52 And the graves were opened; and many bodies of the saints which slept arose, 53 And came out of the graves after his resurrection, and went into the holy city, and appeared unto many.
Again this is a preview of the rapture and the dead in Christ rising, and it is accompanied by a great earthquake just like the opening of the sixth seal. This explains the three days of darkness. When Jesus died he toured Tartarus and preached to the demons and fallen ones in chains. Well, they will be released onto the earth at this time and those left behind will get to tour the Tartarus for three days.