There is a principle in physics called the conservation of mass. This states that in a closed system matter may change in form, but does not increase or decrease. If it appears that something has reduced in volume, something else must necessarily have increased. The total mass of the system remains constant.
It appears that one of the psalmists believed that to be true in Godís system as well. ďMake us glad according to the days wherein thou hast afflicted us, and the years wherein we have seen evil.Ē (Ps 90:15)
We donít live in a stable world. Things change daily. Circumstances change constantly. The pessimist fears that because things are going well, they are bound to get worse. The optimist believes that when things are going bad, they must get better. The pragmatist says both are right. This psalmist tends toward the optimist view because he knows God.
Some things happen to everyone. God is no respecter of persons. ďHe h maketh his sun to rise on the evil and on the good, and sendeth rain on the just and the unjust.Ē (Mat 5:45) Good and bad, drought and flood, light and dark. All are going to happen, and God does not step in to control these things. He allows nature to take its course according to the rules he established at the creation.
That could tend to be a depressing thought, if one does not know God. During the Dust Bowl people wondered if there would ever be an end to the drought. Today, however, Oklahomans say that if God wanted Texans to have grass he would have given them Oklahoma. The cycle continues, no matter how long it takes.
This psalmist prays that the cycle works in equilibrium. For those who follow God, let there be balance. Good equals bad. Joy equals sorrow. He asks that God give joy in proportion to affliction. What does that mean to us?
It means that we can take the optimistic view. When people persecute us because of our beliefs we can know that no matter how bad it gets it will be just as good. When people berate us for our beliefs, God will give us praise in equal proportion.
Blessed are ye, when men shall revile you, and persecute you, and shall say all manner of evil against you falsely, for my sake. Rejoice, and be exceeding glad: for great is your reward in heaven: for so persecuted they the prophets which were before you. (Mt 5:11-12)
But what about when things are going good? Are we to take the pessimistic view that no matter how good it gets we can expect it to get just as bad? It appears that the psalmist believes it is only a one-way equation. Any force acting upon Godís system tends toward goodness. If good acts on the system it doesnít result in an equal amount of evil; it results in an equal amount of good. When evil acts upon the system it results in an equal amount of good. This only makes sense. It is, after all, Godís system and God is good.
God has established laws and principles in the physical world. It seems that some of those principles are mirrored in the spiritual world, as well.