John Calvin on Genesis 20:10

10. What sawest thou that thou hast done this thing ? By this question the king provides against the future. He thinks that Abraham had not practiced this dissimulation inconsiderately; and, since God was grievously offended, he fears to fall again into the same danger. He therefore testifies, by an inquiry so earnest, that he wishes to remedy the evil. Now, it is no common sign of a just and meek disposition in Abimelech, that he allows Abraham a free defense. We know how sharply, and fiercely, they expostulate, who think themselves aggrieved: so much the greater praise, then, was due to the moderation of this king, towards an unknown foreigner. Meanwhile, let us learn, by his example, whenever we expostulate with our brethren, who may have done us any wrong, to permit them freely to answer us.