Hebrews 2:14-15 is a summary of Christ’s work from the time he came to earth through to his crucifixion. By coming to die, Christ defeated the power of death and the one who has power of death. A result of this work is that those who have faith in Christ no longer need to fear death.
Since therefore the children share in flesh and blood, he himself likewise partook of the same things, that through death he might destroy the one who has the power of death, that is, the devil, and deliver all those who through fear of death were subject to lifelong slavery. (Hebrews 2:14–15)
If you struggle with fears about death, consider that Christ died so that we would have hope in life after death. The life that awaits believers in Christ is a glorified life, full of the richness of what God intended humanity to experience. Thanks to Christ’s obedience to God’s plan of salvation, we can be free from fear.
There is much more to say about this passage, and I would like to encourage you to read what John Piper wrote in his devotional for today. If you have not yet downloaded his Advent devotional ebook, you can download it from the Desiring God website.