Impugning motives is the presumption and judgment of another’s guilt without benefit of any further hearing.  Sin …  Is it OK to actually talk about sin anymore?  If faith (good faith) refers to any good faith commitment to enter into a good faith relationship bound by any type of contract, agreement, covenant, offer or trust, then “sin” is the breaching of that relationship regardless of who the parties of that relationship are.  It is equally possible to sin against another person as it is to sin against God.  Therefore “sin” is actually a breach of contract or, perhaps better stated, a breach of relationship.

How then does one breach a contract or relationship?  The signing of such a contract, physical, verbal or implied, is summed up in the voluntary good faith commitment to the relationship and its successful fulfillment.  A breach then, is anything that breaks that commitment, or impedes or prevents the fulfillment of the contract.  The Bible illustrates that under the Old Covenant (contract), any breach of this contract was automatically punishable by death.  

Since every single person that signed that contract did in fact breach it at least once, except Jesus some two thousand years later, you would think that no parties to that contract would be left alive.  And it would be true if not for something God came up with called substitutionary sacrifice, which allowed the party in breach to pay the penalty for the breach through the death of a valuable animal, which stood in the breach making the harmed party whole again and allowing the breach to be covered up or overlooked.

Now many actually did die in breach where it was judged that their breach was a willful, premeditated act.  

In Bible language, this sin was impugned to them by the Lord, (the legal sitting Judge of record in the court of Israel), and some were executed and others died awaiting their execution.  The Lord was able to impugn because He is qualified to be THE Judge but we are not. 

Now we as New Covenant (contract) Christians are qualified to judge, but we are only qualified to judge ourselves.  And if we do that which we are qualified to do, then we are able to make our every breach whole again through Jesus dying as our substitutionary sacrifice.  Under the Old Covenant, one was considered guilty by default until proven innocent.  As born-again New Covenant Christians, because Jesus has paid the penalty of our breach, we are now considered innocent.

Your impugning motive is actually sitting in judgment over another and judging them guilty of breach of contract (sin) against you or another, before you have even heard the entire matter.   And if you are wrong in your judgment, then it is you that is acting in bad faith and are now in breach for defamation of character and potentially ruining a good reputation. 

Even if it turns out that you judged correctly against another, you are now in breach for illegally convening a court and impersonating a Judge (in this case, putting yourself in the place of God).  Either way, the one that impugns the motives of another ends up in breach of contract with someone.

But let’s say that someone actually has breached a relationship.  The question should be: is he or she willing to mend the breach and make all parties whole again?  And if so, he or she should be given the opportunity to do so and then continue the relationship.  And if he or she is indeed willing, but for some reason unable to make things whole; the Bible tells us to show mercy and to forgive the breach. Of course, if he or she is, in actuality, able, but unwilling, to mend the breach then that constitutes a dysfunctional relationship which may need to be discontinued.

In the United States, one is considered innocent until proven guilty.  And before one is judged guilty, there is at least a hearing of the entire matter.  Therefore, it would be wise to follow what the Bible says, “Judge not, lest you be judged.”