"Though he were a Son, yet learned he obedience by the things which he suffered." (Hebrews 5:8)
This verse is a very difficult verse. The Lord Jesus Christ was the very Creator and Sustainer of the universe, the omniscient God, perfect wisdom and complete truth. How could it be that one who knows all things would have to learn anything? Even more particularly, how would He have to learn obedience? He was always obedient to His heavenly Father. "I do always those things that please him," Christ said (John 8:29). He surely did not have to be chastised like a disobedient child in order to learn obedience, as the verse seems on the surface to be telling us.
He was indeed a Son, and He was never disobedient, but He had to become obedient through actual experience. He "became obedient unto death, even the death of the cross" (Philippians 2:8). The "things which he suffered," as the innocent Lamb of God, are beyond all human understanding, and His willingness to obey His Father even in this ("nevertheless not my will, but thine, be done" -- Luke 22:42) demonstrates the ultimate obedience.
There are many things which one can learn in theory, but which are only really learned in practice. The Lord Jesus Christ knew all things by omniscience; nevertheless, He had to learn obedience by actual experience. "For it became him, for whom are all things, and by whom are all things, . . . to make the captain of their salvation perfect through sufferings" (Hebrews 2:10).
Once having passed this test, He had been "made perfect" as the succeeding verse assures us, and thus has become "the author of eternal salvation unto all them that obey him" (Hebrews 5:9). No act of obedience which He urges upon us can ever be as difficult as the things which He was willing to suffer to provide forgiveness and salvation for us. HMM