What does the Bible say about Christians and repeating sin?
The Bible really says little directly about Christians repeating sin. John says, “If we walk in the light, as he is in the light, the blood of Jesus Christ his son continually cleanses us from sin.” (1 John 1:7) Jesus told us to forgive those who repeatedly sin against us, and also said that God forgives us as we forgive others. Therefore, God must forgive repeated sin.
On the other hand, Paul says that we must not intentionally repeat sin. “Shall we continue in sin that grace may abound? May it never be! How shall we, that are dead to sin, live any longer therein? Know ye not, that so many of us as were immersed into Jesus Christ were immersed into his death? Therefore we are buried with him by immersion into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.” (Romans 6:1-4)
Paul goes on to say in chapter 7 that we sin, but we must battle that tendency. We may sin, but we are not to live in sin. We are not to walk in the way of sinners.