Eschatology is a hotly debated subject among modern believers. It concerns the study of the “end times,” last things, or future events in God’s redemptive plan. Its scope includes Christ’s return, the rapture, the millennium, future judgment, and God’s kingdom. Those are all broad and important issues—it’s understandable why a lot of ink has been spilled by people staking out their particular positions.
But there’s also an intensely personal aspect to our eschatological views. And that concerns the only two possible eternal destinations for every person who has ever existed.
“Where will I go when I die?” That is the most crucial question any person can ask. It’s the one facet of our eschatology that we can’t afford to get wrong. And yet too many people ignore that question, and instead become preoccupied with preserving this present earthly life—in spite of its inevitable demise.
Jesus was the consummate theologian on heaven and hell—almost all of our biblical knowledge on these subjects comes directly from His lips. And although He spent His life marching relentlessly toward the cross, He kept the emphasis of His ministry squarely on eternal judgment. He warned His disciples accordingly:
Do not be afraid of those who kill the body and after that have no more that they can do. But I will warn you whom to fear: fear the One who, after He has killed, has authority to cast into hell; yes, I tell you, fear Him! (Luke 12:4–5)
That’s one of the most important eschatological statements in all of Scripture. Jesus tells us what our greatest fear should be. And the thief on the cross is a forceful advocate of that view—his words speak powerfully to those whose primary fear is the end of this temporal life.
The thief suffered the most grueling and agonizing physical death possible. Crucifixion was Rome’s supreme instrument of capital punishment, and a powerful motivational threat for their enemies and subjects. For people in the first century, there was no more dreadful death than crucifixion (and you’d struggle to top it today). John MacArthur adds:
The agonizing pain those crucified endured is almost incomprehensible. The most extreme word in the English language to describe pain is the word “excruciating,” which comes from the Latin word excruciatus, meaning “out of the cross.” 
Source: Grace To You | Cameron Beuttel