How do we know? The Bible tells us so!
Redemption is an act of being saved from sin, error or evil. Similar to regaining possession of.....like clearing a debt. In biblical terms it involves deliverance from bondage based on payment of price by a redeemer.
For believers Jesus has redeemed us from alienation from God through the death and resurrection of his son Jesus Christ. (Ephesians 1:7)
REJOICE-----
REDEEMED ONES!