1)
Are all people's thoughts folly?!
1.
Rashi: Your natural strength to aggrandize yourselves with the crown of kingship - know that this is folly.
2.
Radak #1: He knows that they think that He does not know their thoughts and deeds.
3.
Radak #2: They plan to do something, and Hashem annuls their plans, and they cannot fulfill their intent if Hashem does not know 1 .
1
It seems that this should say 'consent'. (PF)