What is the comparison to Shamayim's height?
Rashi: There is a difference and distinction of levels and praise of My ways above yours, and My thoughts above yours, like the height of Shamayim over Eretz. You put your heart to rebel, and I put My heart to return you!
Radak: This is like David said "ch'Govah Shamayim Al ha'Aretz Gavar Chasdo Al Yere'av" (Tehilim 103:11). This is a great Chesed - when they return to fear Kel, He pardons them and does good to them. Also you in Galus - if you did evil, and I lengthened your Galus, return to Me and seek Me, and you will find Me close to you. The good words that I promised you will cease.
Malbim, from Ikarim 2:4: Do not say that the difference between My thoughts and yours is merely more and less. There is no connection between them at all, just like one does not say that Shamayim is taller than Eretz. Shamayim is tall, and Eretz has no height at all! They are incomparable, just like existence and absence are incomparable. My ways are the ultimate elevation, but yours are not high at all.