"Abraham Receives Sarah from Abimelech", by Nicolaes Pieterszoon Berchem (1620-1683)
In Genesis 20, Abraham tells an untruth and, believing that what Abraham said is accurate, Abimelech acts upon that information. And then God comes to Abimelech in a dream and explains that the information is not true.
Abimelech's Response When a Prophet Says Something That is Not True
He does not lose faith. However he understands that the prophet has said something that is not true and that if he had acted upon that untruth doing so would have caused himself to sin. So he chooses not to act upon it.
It is notable that Abimelech comes to recognize the error after God comes to him in a dream. This determination is not just something that he just assumed based upon his own personal experience. His understanding comes from personal revelation.
Even if the prophet had continued to declare the falsehood he personally would not have lived as though it were truth. He would choose to act according to the personal revelation that he had received.
He was dismayed by the prophet's pronouncing something untrue, but not dismissive or rejecting. He does not accuse. He does, however, seek an explanation.
When the explanation is revealed and it becomes apparent that there isn't even an inspired reason, but that the prophet has based his declaration upon false assumptions Abimelech treats Abraham generously and hospitably in spite of those false assumptions and the lie and, even more impressive, he values the prophet's subsequent prayers on his behalf.
This is a classic example of a noble and appropriate response of a well-intentioned imperfect, good person to a well-intentioned, good,and imperfect prophet (or other ecclesiastical leader).when an erroneous statement by the latter is perceived by the former, by divine revelation, to be damagingly wrong.
Abimelech calls it like he sees it without malice or faith crisis, seeks to understand why the untruth was stated, recognizes the sin that he might have been led to commit if he had assumed that the information was correct, and avoids committing that sin. And he is generous to the prophet and willing to continue to work with him in spite of the prophet's error and he welcomes the prophet's prayers on his behalf.
This is kindness, truth, calm and brotherhood amidst the initial dismay and recognition of error.
In this case that is particularly impressive because the erroneous assumptions Abraham made which led to the lie were about Abimelech himself, something that in most cases would serve to exponentially increase the sense of offence.
Abimelech's response to Abraham is sober and serious but it does not cause him to reject Abraham's prophetic mantle. And his response to his recognition of prophetic error is, ultimately, the moral high ground of kindness, generosity, and hospitality in spite of the error made as well as continued, realistic, appreciation for God's continued calling for Abraham and continued seeking to work with him, rather than against him. (See Genesis 21)
The passage in Genesis 20 refers to God telling Abimelech that Abraham will pray for him after Sarah is returned to her home. And it is clear that those prayers are healing for Abimelech and his household. I have a feeling that after all of this revelation and discussion that Abimelech probably prayed for Abraham too.
In the ensuing months and years both ruler and prophet would benefit from each other's prayers, dignity and desire to do right in spite of Abraham's failure to always do it perfectly then and Abimelech's failure to do it perfectly (he failed to be aware enough of the misdeeds of his bullying servants at a later date) in the future.