While praying, a person should not have any thoughts, but rather become selfless. Even the Holy Fathers say this: “While at prayer, behave as though there were no one else in the world, just you and God.” When praying, we should not be preoccupied with ourselves, because in that case we are so absorbed in our own needs that we ourselves are detrimental to our prayer. We interfere with our own prayer. We are our own obstacle. We often think that evil is somewhere out there, but if it were not for the evil that already exists in us, the evil “out there” would not be able to touch us. The evil is in us. However, this evil itself is not to blame. We are to blame for having let it into our hearts and for having disturbed our peace. Let us say someone is threatening us, or trying to talk us into doing something bad. Let him do so; this person has a will of his own. Let him do his job, and we will do ours, which is to preserve our inner peace.
–Our Thoughts Determine Our Lives, p. 73, Elder Thaddeus of Vitovnica
Forgive me for the constant deluge of quotes from this book. Whenever I come across something enlightening I want to share it with all of you.