To what extent is the narration authentic which states that Ali ibn Abi Talib ceased fighting a polytheist who spat in his face, explaining this by saying: "I was about to kill you because you are an enemy of God, but now that you have spat on me, you have become an enemy to me"?

This narration is baseless and clearly objectionable. How could a polytheist spit in the face of Ali (may Allah be pleased with him) after Ali had gained the upper hand over him? And how could Ali (may Allah be pleased with him) leave him, especially since he did not descend for battle except to fight the polytheists? This act indicates arrogance and pride, and such a person is not to be left alone. Were they acting in a film or fighting a war? Whoever transmits this story should mention its chain of narration or its source in the accredited books.