“And do not lead us into temptation, but deliver us from evil.” (Matthew 6:13, NASB)
The previous portion of the prayer was reactive. We confess and seek forgiveness in reaction to sins already committed. This part is proactive. We pray for God's help to overcome sin in the future. When you put these two into practice in your prayers and walk you will have a repentant lifestyle.
The statements in this prayer are not two distinct statements. They are really two sides to the same coin. That middle word, but, is what gives it away. The way that God does not lead us into temptation is by delivering us from evil. If God does not deliver us from evil, we are lead into temptation.
This tells us about the depravity of our flesh. Unless God Himself delivers us out of our sins, we will always run straight into it. Left to ourselves, we will always gravitate to sin. So this part of the prayer is our asking of God to not leave us to ourselves, but to deliver us.
As Christians, we fight sin and struggle against temptation, but we know it is according to the power of the Spirit within us. So we ought to pray for the Spirit's power and for mercy from God to be able to overcome encroaching sin.