Why did Hashem ask Bil'am the identity of his visitors?
Rashi #1: To trick Bil'am into believing that Hashem does not know everything.
Did Bil'am really believe that Hashem does not know everything?
Rashi: Yes! Bil'am thought that he will be able to curse Yisrael when Hashem was 'unaware'. 1
Da'as Zekenim (citing a Midrash): He is one of three who answered improperly. He should have said 'Hashem, You know everything!' Also Kayin should have said so when Hashem asked 'where is Hevel?', and Chizkiyah, when Yeshayah asked 'from where did the people come to you?' It seems that it should rather say that the third is Adam, when Hashem asked where he is. Chizkiyah spoke to a Navi. Nevi'im do not know everything! Tzror ha'Mor cites the Midrash to say that Bil'am and Chizkiyah answered improperly, and Yechezkel answered properly