1. Jesus means that we speak according to what is (un) consciously admitted by us; that is, what is within us, what is on our minds, our hearts and/or our feelings; whether good or bad.
2. The statement is not correct. Those who steal, taking advantage of the occasion, still hold within them the desire to have something that doesn’t belong to them. The correct phrase is: "The occasion reveals; shows the thief that still exists within the individual."
3. Because what goes on in the mind through our ears or eyes will certainly influence the way we think and act, since we are creatures that oscillate between good and evil. It’s better to always aim to be surrounded by good influences.
4. Yes you can. When watching a violent movie, "getting into" the struggles, the brutality, deaths, destruction, participating on them through excitement, we are assuming that as something good; acceptable. We can incorporate that as our way of doing things.
5. Yes, because anger thoughts shake us too. These make us feel tensed; it prepares our body to fight. This state is highly stressful for our physical bodies. Just observe how quick the blood pressure of an angry person increases once this individual feels angry...
6. Jesus calls attention to the need to monitor our mental field and observe the ideas we're keeping inside our heads, because the way we act depends on that.
7. Yes, of course. Fleeing from malicious anecdotes, swearing, violence, our thoughts will not be pleasing to the spirits who feel delight in evil thoughts. It is a matter of spiritual affinity and options that each spirit can make.
8. Our thoughts can attract good or bad incarnate and disincarnate spirits, according to the law of affinity or sympathy. It depends on our choices. Whoever thinks good things connects to good spirits; whoever thinks evil connects to bad spirits.