Capital punishment is the execution by the state of a prisoner for a capital crime. Capital Punishment is also commonly known of as the death penalty. In the Old Testament, capital punishment was the punishment for murder (Num. 35:16), adultery (Lev. 20:10), incest (Lev. 20:11), bestiality (Lev. 20:15), homosexuality (Num. 18:22), etc.
See the article, What does the New Testament say about capital punishment?