John Calvin Commentary Isaiah 40:13

"Who hath directed the Spirit of Jehovah, or being his counsellor hath taught him?" — Isaiah 40:13 (ASV)

Who instructed the Spirit of Jehovah? What the Prophet had previously taught concerning the Lord’s goodness and power, he now adds concerning His wisdom. We should observe the connection; for our fleshly understanding wickedly limits the power of God to human means, and so it improperly subjects His unfathomable counsel to human reasoning.

Until God is exalted above all creatures, many difficulties arise to interrupt the course of His works; and therefore, if we form a judgment according to our own opinion, various doubts will immediately arise. Thus, whenever we do not see how God will do this or that, we doubt if it will take place, because what surpasses our reason appears to be impossible.

Consequently, just as we should contrast the power of God with our weakness, so our insolence should be repressed by His incomparable wisdom.

By inquiring who guided or directed the Spirit of God, the Prophet means that God had no need of a teacher to instruct Him beforehand about unknown things. Spirit here denotes reason, judgment, or understanding; for He borrows a comparison from human nature, so that He may more fully adapt His way of speaking to people; and I do not think that this should be understood as denoting the essential Spirit of God.