"And as it is appointed for men to die once, but after this the judgment," (Hebrews 9:27)

We are all going to die one day unless Christ comes back.  Because of the fall of man everyone is going to be subject to death.  Because of the sin of Adam and Eve, the curse of death has fallen upon all their descendants:

"Therefore, just as through one man [Adam] sin entered the world, and death through sin, and thus death spread to all men, because all sinned—" (Romans 5:12)

For a true believer in Christ, death should not be feared: 

The bible says:

"Precious in the sight of the Lord Is the death of His saints." (Psalm 116:15)

Here saints refers to all believers.

For a believer to be absent from the body, is to be present with the Lord:

"We are confident, yes, well pleased rather to be absent from the body and to be present with the Lord." (2 Corinthians 5:8)

The Apostle Paul did not fear death.  He said:

"For to me, to live is Christ, and to die is gain. But if I live on in the flesh, this will mean fruit from my labor; yet what I shall choose I cannot tell. For I am hard-pressed between the two, having a desire to depart and be with Christ, which is far better. Nevertheless to remain in the flesh is more needful for you." (Philippians 1:21-24)

Christ delivers from the fear of death:

"Inasmuch then as the children have partaken of flesh and blood, He [Christ] Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil, and release those who through fear of death were all their lifetime subject to bondage." (Hebrews 2:14-15)

For a true believer upon death, he will be immediately with Christ:

"And Jesus said to him [the thief who believed on Him], “Assuredly, I say to you, today you will be with Me in Paradise.”" (Luke 23:43)

For a believer, Heaven is assured:

"Now I saw a new heaven and a new earth, for the first heaven and the first earth had passed away. Also there was no more sea. Then I, John, saw the holy city, New Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband. And I heard a loud voice from heaven saying, “Behold, the tabernacle of God is with men, and He will dwell with them, and they shall be His people. God Himself will be with them and be their God. And God will wipe away every tear from their eyes; there shall be no more death, nor sorrow, nor crying. There shall be no more pain, for the former things have passed away.” Then He who sat on the throne said, “Behold, I make all things new.” And He said to me, “Write, for these words are true and faithful.”" (Revelation 21:1-5)

For a believer in Christ, death is not the end for he has eternal life:

"Jesus said to her, “I am the resurrection and the life. He who believes in Me, though he may die, he shall live." (John 11:25)

"For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life." (John 3:16)

"For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord." (Romans 6:23)

"“Most assuredly, I say to you, he who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life." (John 5:24)

A believer in Christ has hope of eternal life but those who do not know Christ as Lord and Savior do not have this hope.