At first that Christ learned obedience (Hebrews 5:8) looks like a contradiction: How can He learn if He already knows everything?
But we know from mathematics that behavior of infinite things is different than of finite ones: For example, if we move an infinite plane, it remains in place. If we increase its size, it remains of the same size. In the same way Christ expands His knowledge while His knowledge is already complete.
Nearby verses of the Bible emphasize that Christ is the Son of God. “Son of God” means “infinite development, infinite grow” as to grow to become similar to the Father is the main property of a son. Thus Christ learns all the time.
(Heb. 5:8) “8 Though he were a Son, yet learned he obedience by the things which he suffered; 9 And being made perfect, he became the author of eternal salvation to all them that obey him”.
We see that He learned a certain thing, obedience. To learn obedience is not the same as to learn something outside of us, it is to learn about what is inside us, our own obedience.
We see that despite of being exceedingly great, Christ is like a regular child: He does not want (exercise to find a verse in the Bible) to learn obedience by suffering. He obeys the command of the Father unwillingly, “Let not my but Your will be!”
So Christ did not love mankind so much to be willing to suffer for us. He wanted to leave this game. He wanted to abandon the mankind and stop doing good for us. He is much more important than the mankind. (In fact He is much greater as he the “light” (electromagnetic energy) of the universe and thus occupies the entire heaven.) Father send him to sufferings to teach Him something, saving mankind was a secondary purpose.
(Heb 5:9) “And being made perfect, he became the author of eternal salvation to all them that obey him.” After He learned, He was able to become the author of a very difficult thing, salvation of sinners.
Recently Christ has terminated the New Testament and stopped salvation of unrepented sinners. He enjoys this ending of a punishment from the Father, what for Christ was being solving this difficult task to save the people.