What does 'thou shalt not die' mean in a Christian context?

In the Christian context, the phrase 'thou shalt not die' primarily refers to the assurance of eternal life granted to believers in Christ. This promise was provided to David by the prophet Nathan as a comfort for his sin (2 Samuel 12:13). It signifies deliverance not from physical death, which all eventually face, but from eternal condemnation and separation from God. Revelation 20:6 encapsulates this promise: 'Blessed and holy is he who has a part in the first resurrection; over these the second death has no power.' The assurance that we shall not die spiritually allows believers to rest in God's grace, free from the fear of eternal judgment.