I have also often been tormented by this passage - and also by Jesus' words immediately following his recital of the Lord's Prayer:
"For if you forgive men when they sin against you, your heavenly Father will also forgive you. But if you do not forgive men their sins, your Father will not forgive your sins." Matt 6:14,15
These situations appear to be so absolute. If I do not forgive others for their sins against me then God will not forgive mine. There is no hint of partial solutions here, it is all or nothing. Yet how can one forgive every person for every sin they commit against us whilst being such imperfect persons ourselves?
It is maybe easier to forgive when sins occured back in the past and with no current continuation, but how does one forgive someone whose sin against us continues day after day?
In addition, although we may think we have forgiven someone for their sin against us in the past, what happens when they repeat the same sin in the future, do we not resurrect the old sin and join it with the new one and create an even greater sense of maltreatment?
If salvation is purely dependent upon God's grace and not in any way the result of our own input, how can God's willingness to forgive us hinge on our own track-record in the forgiveness of others?
At the very best, I can achieve a state of neutrality towards the sins of others by passing on the burden to God as judge and jury, but is that forgiveness? I don't think so. The ability to truly, absolutely and unconditionally forgive others is beyond my scope as a human.
If, therefore, forgiveness remains beyond the scope of a human, then something else lies beyond this. Just like love, hope, faith, perseverence, and other Godly attributes, forgiveness does not come from the human heart but via the human heart. The source of all goodness is the same. The conduit for all goodness is the same. So, it seems, once again the answer to forgiving others lies only in keeping one's eyes focussed purely on one's faith in God alone.
As in all things:
"With man this is impossible, but with God all things are possible" Matt 19:26
