Why did Christ die for believers?
Christ died for believers so that they obtain salvation by our Lord Jesus Christ, are not appointed to wrath, and will live forever with Him. Whether they are alive or have died, the purpose is eternal life with Him. This is what His death accomplished for believers.
Les explains that the believer is not appointed to wrath or designated to suffer the awful events of the tribulation before Christ comes; instead, believers will be taken out ahead of it. The text says Christ died for us so that, whether we wake or have died, we will live forever with Him. So His death secures salvation and eternal life with Him for believers.
Ephesians 4:9
(Now that he ascended, what is it but that he also descended first into the lower parts of the earth?