Louis Berkhof points out that death is not necessary for sanctification, for Enoch and Elijah were made perfect without experiencing death. Nor is it absolutely essential for delivering us from this present evil age, for God may do this without the instrumentality of death, as he most certainly will for those who remain alive at Christ’s Second Coming (1 Thessalonians 4:13-17). Rather
“[t]he very thought of death, bereavements through death, the feeling that sickness and sufferings are harbingers of death, and the consciousness of the approach of death, – all have a very beneficial effect on the people of God. They serve to humble the proud, to mortify carnality, to check worldliness and to foster spiritual-mindedness. In the mystical union with their Lord believers are made to share the experiences of Christ. Just as He entered upon His glory by the pathway of sufferings and death, they too can enter upon their eternal reward only through sanctification. Death is often the supreme test of the strength of the faith that is in them, and frequently calls forth striking manifestations of the consciousness of victory in the very hour of seeming defeat, 1 Peter 4:12-13. It completes the sanctification of the souls of believers, so that they become at once ‘the spirits of just men made perfect,’ Hebrews 12:23, Revelation 21:27. Death is not the end for believers, but the beginning of a perfect life.” Louis Berkhof, Systematic Theology, 1939,1941 (Grand Rapids: Eerdmans, 1979), 670-671
The fact of our future death should cultivate a seriousness about life that makes personal holiness a pre-eminent concern. Truly, to the believer, the thought of death is a sanctifying influence.