People inflict suffering to each other sometimes without any reason. In the sixteenth Chapter of the "Bhagavad-gita" Krisna explains what is the reason behind it. This chapter of the is very relevant in the modern world, because we see that the demoniac forces become stronger and stronger. If we know very well what Krisna says in the "Bhagavad-gita", it can be like a vaccine against this demoniac mentality. Therefore we can take this vaccine every day.
All diseases are coming from the mind. If we purify our mind by reading "Bhagavad-gita daily", then we will be diseases-free. Our body will be free from disease, our mind will be free from disease, our society and our family will be free from disease.
The seed of demoniac mentality is the denial of God's existence. They say that this material world appeared just by chance. But nothing happens by chance. People don’t believe in God because they don’t want to obey His will, they want to do what they want. The meaning of their life is just to squeeze out material enjoyment as much as possible. This is a very destructive mentality, everything around such people is being destroyed.
We are very pure by nature, but under the influence of bad association we become impure. Because of this, destructive mentality takes over and we start destroying ourselves and everyone else. The only protection from this destructive mentality is faith in God. The best way to strengthen faith in God and to get the real experience of God is to chant His Holy name. The only possibility to protect ourselves from contamination, which is coming from outside, is to chant Hare Krisna Maha-mantra.
There are two natures: demoniac and divine nature. We have both these mentalities and the battle between them is going inside. To strengthen divine nature we chant Hare Krisna, preach and read the "Bhagavad-gita".