The Greek apokatastasis means restoration, reestablishment, or the restitution to an original or ideal state. It appears once in the New Testament (Acts 3:21) in Peter's sermon at Solomon's Portico, referring to the eschatological restoration of all things promised through the prophets.
Apokatastasis is Peter's summary of biblical eschatology: Christ must remain in heaven until the time comes for God to restore everything (Acts 3:21). This is not universalism (a view that all people will ultimately be saved), despite Origen's later use of the term — in context, Peter is describing the fulfillment of prophetic promises about Israel, creation, and the Messianic age. Paul echoes it: 'creation itself will be liberated from its bondage to decay' (Romans 8:21); 'God was pleased to reconcile to himself all things... through the blood of his cross' (Colossians 1:20). Revelation 21-22 portrays the final apokatastasis: a new heaven and earth, the New Jerusalem, no more curse, God dwelling with His people. The word is a promise: nothing that sin has broken will remain broken forever.