Heb 5:7-6:1 In the days of his flesh, Jesus offered up prayers and supplications, with loud cries and tears, to him who was able to save him from death, and he was heard because of his reverence. Although he was a son, he learned obedience through what he suffered. And being made perfect, he became the source of eternal salvation to all who obey him, being designated by God a high priest after the order of Melchizedek. About this we have much to say, and it is hard to explain, since you have become dull of hearing. For though by this time you ought to be teachers, you need someone to teach you again the basic principles of the oracles of God. You need milk, not solid food, for everyone who lives on milk is unskilled in the word of righteousness, since he is a child. But solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil.
An interesting fact stated here is that Jesus did not become "perfect" but was "made perfect" through the things he suffered. The word "perfect" (teleioo) is not a static concept but dynamic one. It means to bring a process to its completion. When Jesus cried out on the Cross, "It's finished!" (telelestai), he meant that the task has been completed--it's perfected. So when Jesus said we are to be "perfect, as your heavenly Father is perfect" (Mt. 5:48), he is calling us to become morally complete--by learning to love not just our friends but our enemies as well because God "sends rain on the just and the unjust" (Mt 5:45). So the perfection Jesus speaks of is about becoming like true "sons of the Father" viz., loving our enemies. That is perfection--becoming like our Father in heaven.
As a man, Jesus himself had to go through the process of maturing--emotional, mental and physical--as he progressively learned how to obey His Father. He finally reached "perfection" when he submitted his own will to the will of the Father, even to the point of dying on the Cross: "Not as I will but as You will" (Mt 26:39). So Jesus was "made perfect" because he completely and unreservedly submitted to the will of Father, willing even to suffer in order to accomplish the purpose of becoming "the source of eternal salvation to all who obey him" (Heb 5:9). So the "perfection" that Jesus calls us to become is the perfection of submission to the will of God.
But this is hard saying for those who only want milk not meat. The writer to Hebrews describes such people as "unskilled in the word of righteousness, since he is a child" (Heb. 5:13). Instead of moving upwards towards perfection, they are sliding backwards towards immaturity. But such solid teaching--that we have to endure suffering in order to learn obedience--is too hard for someone who is behaving like a child. A child will cry and protest when he or she has to suffer to get what he or she wants. But only the matured person will endure suffering for the greater goal. So, such "solid food is for the mature, for those who have their powers of discernment trained by constant practice to distinguish good from evil" (Heb 5:14).
I've heard so often people migrating from church to church because they feel they are not "growing" in a particular church. But growth does not come just by listening to great sermons but by obeying the will of God. We are not made perfect by constantly seeking for self-edification. We are made perfect when we learn to die to self-centredness by saying, "Not as I will but as You will." That is perfection for the spiritually matured.
Father, teach us to be perfect even as You are perfect. Help us learn obedience by enduring sufferings. Amen.