Certain monotheistic strains of Greek philosophy emphasize that God is perfect. Most Christians and Christian theologians find this idea appropriate. The question is not whether God is or is not perfect, the question is how perfection is to be understood. For some, such a consideration seems nearly foolish. My hope is that you find what follows to be helpful.
The standard concept that surfaced with the Greek philosopher was that a perfect being could not experience change on any level. The reasoning was, “If they change for the better, they were not perfect before they changed, and if they change for the worse, they are not perfect after they change.” So, change is out. A perfect being cannot change. Though this sounds quite convincing to many people, there are forms of perfection that require some measure of change.
As an illustration, we might consider a clock. A clock that does not change is only right twice a day. A clock that does not change is not a perfect clock. Some measure of appropriate change is necessary for a clock to be perfect. Of course, a clock that changes inappropriately (too fast or too slow) is not a perfect clock. So, let me emphasize that perfection does not necessitate changelessness but, rather, appropriate change.
Another example involves a personal, not merely mechanical, response. If a room full of people were joking, laughing and having a jovial time and friend entered the room and announced with great grief that their husband had just been killed in a horrible accident, having no changed emotional reaction would not be a sign of perfection. Perfection would involve an appropriate change of emotional and personal response.
Attempting to develop a theological perspective through the Greek view of perfection creates problems. It is even more difficult to develop a Biblical view of God from this Greek view. According to Scripture, God, perfect in His moral responses, changes in an appropriate manner and measure. He, in His perfection, will not change His loving moral character. We should swing neither in the extreme of declaring that God cannot change in any manner or measure, nor the extreme fear that God will change in an inappropriate manner or measure. We trust that even concerning change, He is perfect.
The next time we will consider how to understand a Biblical statement such as, “…I am the LORD, I change not…” and the statement, “…you are to be perfect as your heavenly Father is perfect.”
 Both illustrations are borrowed from Dr. Gregory Boyd.