Jesus clearly explained not once but several times in the gospels, including in His model prayer (commonly referred as the Lord’s Prayer), that we must forgive others without which we cannot receive forgiveness from the Father.
Matt 18:21-22 Then Peter came to Jesus and asked, “Lord, how many times shall I forgive my brother or sister who sins against me? Up to seven times?” Jesus answered, “I tell you, not seven times, but seventy-seven times.
Matt 6:14-15 For if you forgive other people when they sin against you, your heavenly Father will also forgive you. But if you do not forgive others their sins, your Father will not forgive your sins.
Forgiving is so important that if we fail to do so, our sins will not be forgiven. As in the parable of unforgiving servant, even our forgiven sins will be unforgiven and punished for it, if we fail to forgive others.
John 20:23 “If you forgive the sins of any, they are forgiven them; if you retain the sins of any, they are retained.”
However, after the resurrection of Jesus said a different statement to His disciples contrary to the core message of the other three gospels that they can retain sins of others if they want and it will not be forgiven for them.
Inconsistency in gospel of John
We do not know why it contradicts with other gospels. What we do know is, John is very old when he wrote this gospels and it is based on his recollection. To test which message is correct, we can test the very quote claimed to have been spoken by Jesus in the gospel of John.
John 20:20-23 When He had said this, He showed them His hands and His side. Then the disciples were glad when they saw the Lord. So Jesus said to them again, “Peace to you! As the Father has sent Me, I also send you.” And when He had said this, He breathed on them, and said to them, “Receive the Holy Spirit. If you forgive the sins of any, they are forgiven them; if you retain the sins of any, they are retained.”
John 16:7 But very truly I tell you, it is for your good that I am going away. Unless I go away, the Advocate will not come to you; but if I go, I will send him to you.
The Holy Spirit given on the day of Pentecost, that is fifty days after Christ’s resurrection according to Luke as we read in the book of Luke (Luke 24:49) and Acts (Acts 1:4-5). John, however, mentions about the Holy Spirit given on the day of resurrection of Jesus and not on the day of Pentecost. Based on what Jesus spoke earlier that He must go to send the Holy Spirit in the gospel of John (John 16:7) and what happened on the day of His resurrection where He not yet ascended to the Father but giving the Holy Spirit in the same gospel, we can conclude that this particular event on how the Holy Spirit was given in the gospel of John is incorrect. This was explained in the post, When was the Holy Spirit given?
It is in this same quote (John 20:20-23) where Jesus tells His disciples to retain sins if they want after giving the Holy Spirit. Undoubtedly, John’s recollection on the details of how Jesus appeared to His disciples on the day of resurrection is inaccurate. It is improper for us to blame John for giving a small detail wrong since it was a recollection of an event that happened nearly sixty years earlier by a very old man, probably in his nineties.
Matt 6:15 But if you do not forgive others their sins, your Father will not forgive your sins.
Mark 11:26 “But if you do not forgive, neither will your Father in heaven forgive your trespasses.”
Luke 17:3 “Take heed to yourselves. If your brother sins against you, rebuke him; and if he repents, forgive him. And if he sins against you seven times in a day, and seven times in a day returns to you, saying, ‘I repent,’ you shall forgive him.”
As a matter is resolved by two to three witnesses, we have all the synoptic gospels giving witness that we must forgive sins of others and not to retain them.
Jesus taught that forgiving is so important that if we fail to do so, our sins will also not be forgiven by God. But John writes about Jesus teaching to retain sins. A closer look at the quote of Jesus reveals that the details of that event was clearly wrong due to John’s recollection of the event later. Hence, we must forgive others and not to retain sins as all the synoptic gospels say.
Please read the followup post, Responsibility of rebuking before forgiving after reading this post. When a person who repeatedly keeps sinning against us, comes and says ‘I repent’, we must forgive every time he asks forgiveness as mentioned here. However, even after rebuking through several means, if he still didn’t repent we don’t need to forgive him but treat him as a stranger.