The Holy Bible is clear in showing that God kills believers in punishment. This is evident in the Old Testament in the Book of Exodus, in which God killed believers who created and worshipped the Golden Calf. It is also evident in the Book of Acts, where believers did not pay the promised donation to the church.
Much of the suffering by believers is due to their sin, and this is clear in the Book of Exodus and other books of the Holy Bible.
Bible is clear that God kills believers in divine punishment? Why?
(1) Because God is a just and righteous God who punishes every sin on earth. You may be forgiven of your sins and may enter into Heaven, but on earth you will be punished for every sin, even those for which you are forgiven. It would be unfair and unjust to Christians who do not sin, if God lets you go free on this earth. Example: Should a Christian teen who fought sin and remained a virgin until marriage be treated the same as a Christian teen who had pre-marital sex? Of course, not! God is fair and God is just, and that is why God punishes believers for sin on this earth, even after He forgives them.
(2) God sometimes kills believers in divine punishment to stop them from continuing to sin. This is clear in the usage of drugs, like opioids. Overdose on drugs is a form of divine punishment for believers who use drugs. They may be sorry and repent, but when God sees believers continuing to sin again and again by using drugs again and again, God can kill such a believer to stop him or her from continuing to sin, again and again.
(3) Killing believers who sin against God brings God glory. God is glorified when He punishes people for sin. This principle is emphasized in the Old Testament as well as in the New Testament. Read Jeremiah, Isaiah, Revelations, etc.