Keil & Delitzsch

The appeal, to leave their own way and their own thoughts, and yield themselves to God the Redeemer, and to His word, is now urged on the ground of the heaven-wide difference between the ways and thoughts of this God and the despairing thoughts of men (Isa 40:27; Isa 49:24), and their aimless labyrinthine ways. "For my thoughts are not your thoughts, neither are your ways my ways, saith Jehovah: no, heaven is high above the earth; so high are my ways above your ways, and my thoughts above your thoughts." The kı̄ (imo) introduces the undeniable statement of a fact patent to the senses, for the purpose of clearly setting forth, by way of comparison, the relation in which the ways and thoughts of God stand to those of man. There is no necessity to supply כאשׁר after כּי, as Hitzig and Knobel do. It is simply omitted, as in Isa 62:5 and Jer 3:20, or like כּן in Pro 26:11, etc. On what side the heaven-wide elevation is to be seen, is shown in what follows. They are not so fickle, so unreliable, or so powerless.