Buddha was speaking about reality. Reality may be one, in its deepest essence, but Buddha also stated that all propositions about reality are only contingent. Reality is devoid of any intrinsic identity that can be captured by any one single proposition - that is what Buddha meant by "voidness." Therefore, Buddhism strongly discourages blind faith and fanaticism.
To define Buddhism without a lot of words and phrases, we can simply say, 'Don't cling or hold on to anything. Harmonize with actuality, with things as they are.'
One interesting thing about greed is that although the underlying motive is to seek satisfaction, the irony is that even after obtaining the object of your desire you are still not satisfied. The true antidote of greed is contentment.
To observe and watch one's own mind is something really interesting. The untrained mind will run and follow its old habit patterns. Because it has not been trained and taught, it will get lost in all kinds of stories and issues. Therefore we have to train our mind. The meditation practice in Buddhism is all about training one's own mind.
Solitude is happiness for one who is content, who has heard the Dhamma and clearly sees. Non-affliction is happiness in the world - harmlessness towards all living beings.