If we accept Christ into our lives, our sins are forgiven (past, present and future). Therefore, why are we told to pray for forgiveness for our sins? If a believer asks God to forgive his sins, isn't that a lack of faith in God's promises, since you are asking Him for something He has already given you?
A. In one sense, your statement is correct. The Bible teaches that a person need not ask for saving forgiveness more than once. In other words, once we have appealed to God for mercy, trusting upon His Son to save us from the penalty of sin, then we are saved and will never bear the punishment for our sins. As Paul summarizes in Rom. 10:9: "that if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved..." Nothing more is required.
On the other hand, a Christian is also called by Scripture to maintain a repentant heart, routinely acknowledging sin and seeking God's grace and mercy in the midst of his daily mistakes. These activities are not done with the intent to secure or maintain salvation, yet they are expected nonetheless.
VBVMI uses a simple convention to explain the distinction between two kinds of repentance described in the Bible. You could say that the Bible teaches the need for Repentance (with a big "R") and repentance (with a little "r"). Repentance (big "R") refers to the repentance that happens during our salvation moment. This is a repentance from dead works and a life lived apart from God. It acknowledges we are sinners and in need of God's mercy and forgiveness if we are to avoid the penalty of sin, which is eternal death.
This repentance is an unique kind of repentance that only the Holy Spirit can produce in the heart of an unbeliever, which leads to acceptance of the Gospel, as Paul states:
The second kind of repentance (a little "r") is the regret or sorrow that believers experience dailiy when convicted of their sinful behaviors. Becoming a Christian removes the penalty of sin, but it doesn't (immediately) remove the reality of sin in our earthly life. So, we have need for this secondary form of repentance, which is also the work of the Holy Spirit, to produce a sanctifying process. As the Holy Spirit convicts believers of daily sin, He is prompting repentance and leading us into a more Christ-like life.
This second kind of repentance isn't an appeal for saving forgiveness - we already have that by faith. Rather, it is an appeal for God to forgive us from the consequences of our sin. We aren't appealing for relief from Hell; we're appealing for relief from the discipline of the Lord. Much like a son appeals to his human father for mercy to avoid punishment, we ask the Father to spare us as well. And John says the Lord will forgive us in this way if we repent:
There are a couple of good examples (among many) in Scripture to illustrate this principle of repentance for the believer. First, consider Jesus' instructions to the church of Ephesus in Revelation:
Jesus told the church in Ephesus that they must repent of their poor witness (i.e., leaving their first love), or else He will end the church's very existence. Here we see a connection between a believers' sin and God visiting the consequences of their sin upon them. If the church didn't repent of their sin, Jesus would visit the consequences of their sin upon the church.
Likewise, if believers live in unrepentant sin, they will see the consequences of their sin visited upon them as discipline from the Lord. As the writer to Hebrews 12:7-11 says plainly:
A second example is found in the life of David in 2Sam 12:13-16:
In 2Sam 12, David is praying and fasting for the Lord to spare his son, who is near death. David knows that his son's condition was brought upon him by the Lord as punishment against David for his unrepentant sin with Bathsheba. David prays for the Lord to show mercy instead. The Scripture says plainly that David's sin has already been taken away by his faith, so salvation was not in question. Nonetheless, David feels the need to pray for forgiveness, because he wishes to save his son.
The Lord bring discipline against David because of his sin, and even knowing his has been forgiven, David still prays for mercy for his son's sake. Obviously, the Lord rejected David's plea and takes the son anyway, but this is an excellent example of why a believer may pray in repentance even though salvation has removed the penalty of sin: we still may bear the consequences of our sin in this life.
Clearly, the Lord expects believers to pray for forgiveness even after we are saved, but we do it for a different reason than the one we had before faith. Before faith, we prayed with a repentant heart longing for forgiveness leading to eternal life. Now having been saved, we still pray for forgiveness from the consequences of our sin.