There are many causes which generate trials and sorrows in our life. Besides that, their combinations can be quite complex, so we are in a labyrinth of factors.
However we can distinguish four big categories of influence which will help us to avoid and protect ourselves from unwanted happenings in our life.
Sorrows because of our sins.
When we sin, because the sin is an existential distortion, spiritual law will try to re-establish the equilibrium. If we will try by ourselves, through repentance, confession, and asking for forgiveness to fix our mistake, then sorrow will not come. Otherwise, it will happen after a certain time when it will be clear that we didn’t have an analogous repentance.
We make a plan and begin to follow it. However, we cannot see too much in advance. God, which knows everything, sees that in front of us is a deep tar pit, a trap which will harm us badly. That’s why He will allow a blocking trial to happen in order to close our path towards the trap. That’s why the Holy Fathers say, “When God closes a door, don’t break the doorknob”. You will repent of it after.
Someone can advance spiritually but (s)he cannot or (s)he doesn’t want and/or (s)he doesn’t know how to advance. In such cases, God gives us a trial, a sorrow, in which we will gain virtues like prayer, patience, humility, and other qualities upon which we will advance spiritually.
Trials, for example.
Everyone is a sinner but there are times in which we don’t do such sins in order to trigger the spiritual law in a big degree. Even then, God might put us in a trial in order to be an example to follow, a light for others. We have here the classical example of Job in the Old Testament period. In the New Testament period, there is, firstly, the example of our Lord Jesus Christ and, after Him, a lot of saints.
Based on Elder Joseph of Vatopaidi, Saint Paisios the Athonite
Source: Ascetic Experience