Our suffering is due to sinful activities. And sinful activities are due to our ignorance. Ignorance. Sinful activities are done by persons who do not know what is what. Just like a child. A child does not know what is the result of catching fire. Because he is ignorant. But as soon as the child catches fire, his hand becomes burned immediately. The fire does not allow any concession for the child. It will act as fire. Similarly, we do not know how this material world is going on, what are the laws, who is the controller, how it is being controlled. Due to our ignorance, we act in some way, but nature is so stringent that it will never excuse you, either you do it knowingly or unknowingly. Just the same example: the child does not know that the fire will burn, but if the child catches the fire, the fire will not excuse because it is child. Therefore ignorance is the cause of suffering.
And one should be put into proper knowledge. Proper knowledge means to know things as they are: "What I am, what is this world, what is God, what is our relation." These things we should know, not that simply becoming a technical expert or some departmental expert, we become a man of knowledge. That is not knowledge. Here is knowledge. You should know what you are and how you act.