Shabbos 11a: The kingdom must have so many things in mind, that they could not be written down even if all the seas were ink, and all the swamps were quills, and Shamayim was parchments, and all people were scribes.

Rashi: There is no measure to the height of Shamayim, the depth of the land, and the heart of kings - how many judgments come in front of them, how many wars they must heed... If all tongues would talk, and all hands would write, they cannot write this.

Malbim: There is no measure to the height of Shamayim, for it spreads out above without end. In the expanse of Shamayim there are innumerable worlds. One cannot investigate them, due to their abundance and height. The land is like a small point compared to them. It cannot be investigated due to depth. The depth is covered with the great Tehom; what is in the depth of the Tehom is not known. Also the heart of kings cannot be investigated - conduct of the kingdom spreads over nations without number, and individuals without limit. Also, their conduct includes deep things and royal secrets that cannot be investigated.